Pacing is everything on a long retreat and you have to find out what actually works for you. Think about intensity of practice, schedule of practice, and methods of practice before you go. This is my personal advice, but only you know if it works for you.
For some people "practice your butt off" is the way to go. For me, I just burn out every single time I take that approach. You might feel compelled to do that approach, but I can't in good conscience recommend it.
I actually recommend the "for every single moment of retreat, I will go into the experience of actually being on retreat. I will become intimate with everything I sense, feel all the primal urges, experience all the tones of emotions, and notice what I think as thoughts." I also throw away all goals and say "may whatever happens on retreat be for the benefit of all beings, including myself. May all beings benefit from me being on retreat. May I experience on retreat whatever will bring the highest benefit for myself and all beings." Goals are great, but why not have the highest goal?

So without bring an external agenda besides my mode of practice, I go deep into the feeling of being an actual human on retreat. I find that this keeps me grounded and whole. Retreat becomes delicious. Hard at times for sure, but always rich. Rich with pleasure, rich with wonder, rich with times of endurance, rich with times of rest. That richness of experience is the main thing to keep constant. The acutally tone of the richness will change throughout the retreat. Don't script yourself into thinking it always needs to be torture to make progress. Absolutely not true. It can and should be a delight to rest in the pleasure of seclusion, as the suttas say.
The other side of it is I keep to the practice schedule, unless there is a very very good reason not to. So if it's sitting time, I'm sitting. If it's walking time, I'm walking. This becomes very hard after a while. There can be a desire to mix it up, to make it more interesting. But I find that these urges are avoidance mechanisms. Look into the ill will that wants to mix things up. Chances are you'll find greed, aversion, and ignorance. Now of course fine tune the schedule to work for you. I know I wake up early and benefit from a post lunch nap, so that's what I do. I know I don't stay up as late as other people and want to go to sleep early, so that's what I do. Within that, I find alternating hours of sitting and walking to be just about right.
For walking, you want to focus on relaxing the body, relaxing the aches, freely swinging the joints to help keep your body recovering from all the sitting practice. You will feel sore and tired, but gently walk, gently flush the muscles. It's totally normal to go through a period of deep aches and pains. Make sure you vary the pace and walk both quickly and slowly at times, feeling what seems right. You don't need to walk slowly, this is a wierd hang up people have. The mind is very very very fast. You can stay mindful as you walk somewhat briskly. If you are feeling dull, try walking a little quicker. If you are feeling manic, SLOW DOWN. The main thing is to walk at the pace where you stay mindful of what you are doing and walk at a pace where you can feel yourself relax.
Remember mindful eating, mindful peeing, mindful shitting, and mindful showering, mindful putting on clothes, mindfull taking off clothes, mindful brushing of teeth, mindful combing of hair. Never come off retreat. Always be richly in your actual experience. Big experiences happen at the strangest time (flipping the lid on a shampoo bottle) so always stay richly in your actual experience. Every experience is important. I kinda want to put that in caps: EVERY EXPERIENCE IS IMPORTANT

(Have you read this article? https://www.dharmaoverground.org/dharma-wiki/-/wiki/Main/Jhana+and+%C3%91ana+ Check out the part about being a western dark night yogi.)
For practice, I would say the biggest thing for a dark night yogi to do is to learn to gently but continously note sensations, urges, emotions, and categories of thought while sitting. By gentle I mean a verbal note of something -- anything -- in experience on each out breath. (So I'm recommending verbally noting about 8 to 12 times a minute.) Meanwhile, intimately notice all of the other sensations, urges, emotions, and categories of thoughts that are occuring. This is the "richness" of experience that I was talking about earlier. This means you are doing about 80-90% noticing and about 10-20% noting/labeling. That's a good sustainable ratio and has a balance of going deep without becoming manic.
It is important for a dark night yogi to allow him/herself to experience pleasure when it arises. Rather than thinking "concentration" think "centering yourself". When pleasure arises, put yourself in the center of it. Delight in it. Enjoy it. Know that buddha highly recommended this kind of karma-free delight. Don't worry about vipassina when pleasure arises --- this will feel wrong to a dark night yogi, but this is actually why someone is a dark night yogi. When delight arises, enjoy it and wish for all being everywhere to also experience delight in their life. Be like a lightout sending out this joy and delight to everyone.
There will be hard crashes as well. Dark night yogis have guilt complexes, persecution complexes, fears, deep feelings of inadequacy. It's important to remember that you are noticing all of these things in awareness, but you are not these things. These are old habits of mind that are showing themselves to you, so that you can clearly see them. You can clearly see how they are primitive urges that are trying to be helpful, trying to protect you, trying to keep you safe... but they are simply not appropriate anymore. It's time to let them go. Don't force them away, but simply allow them to come and go. Let those primitive states of mind feel your attention, even send them some love and kindness. Be gentle with the shadow side of your psyche, all it really wants is your love and respect.
Sometimes it can be helpful to zoom into whatever feels "bad" or like "ill will" ask, is this greed, aversion, or ignorance/fantasy? That can be an interesting question, although you don't necessarily need an answer every time. Regardless, after you spend some time being curious about it, send that bad feeling some metta or good will.
A dark night yogi kinda secretly wants to have all the bad stuff beaten out of him/her. A dark night yogi often is intimidated by love, healing, and joy. Use this retreat to drop the masochism and build new habits. Be gentle with yourself, but stay disciplined. Be kind to yourself, but keep the practice schedule.
Best wishes!