This is a question for those who have practiced for a longer time.
It's not really practical but maybe interesting.

According to MCTB and more or less general consensus, the nanas just go on and on and keep changing forever.
But the spectrum essentially remains the same.

I wonder though if the proportions change over time.
My guess would be that you become more and more neutral, i.e. equanimity becomes a more frequent experience.
Is that true?

What were your experiences in this regard, and also about other nanas?
For example "early in my practice, dissolution was this big thing, which took so long and would get me stuck in it, but later it only ever occurred for a few minutes."
Or "the longer I practiced, the shorter/longer/more boring/more intense" different nanas became.

I wonder if there are common changes, or even if there are any such changes to individual practitioners.

I've only been paying attention to the nanas for about three years, so I don't know if that qualifies as a long time.  Regardless, here are some changes that I've noticed in that span:

-The EQ nana has become way shorter.  The different parts of the eq nana have become less discernable.  
-The difference between the first 3 nanas has become more clear.
-Spontaneous A&p's have become more intense, and more meaningful.
-Fruitions have become less of a 'big deal.' 
-The dark night has become way shorter and easier to deal with, along with hindrances in general.  There have been major exceptions, including times when I have gotten lost in obsessing and/or depression for weeks.

Have I gotten it right that nanas pre-SE can take months or years but after SE there are several A&P-DN-Low EQ and back again loops a day?

I would say its probably more mixed.  Regardless of whether one has SE, the more one progresses through the nanas (purposefully or not), the more those rails are greased, and the faster it will have the potential to cycle next time.  There are definitely still times when people will randomly get stuck in a given nana for longer periods.  

My GD buddies thought cycling every day sounded like bs, but maybe they mean something else with cycling or their path is just another thing completely. 

Yea its probably just out of context.