Hi Mike,
One thing that I found surprisingly helpful to initially enter tranquillity was to consciously relax my body, by imagining and inviting it to be comfortably warm, heavy, and soft, a kind of sinking-into-the-pillows effect. Especially with the candle flame, since it's so easy to go rigid with the strain of staring fixedly at one thing.
For example, relax on the in-breath, relax on the out-breath. Whole body, from the top of my head to the weight on my buttocks or feet (if standing), including shoulders and fore-arms and face.
One other thing was that I found counting too complicated and used a simple meditation word instead, which I kept going all the time (whenever I remembered to). I'd imagine "listening to" this word, find out how it "sounded". The breath would then join in of its own accord sometimes, which was nice, but apart from letting myself breathe freely (not pulling in the gut), I left the breath alone when doing that.
As to doing vipassana automatically: yeah, can happen. You could try to use formal resolve to have a concentration state arise.
Enjoy! Tranquility can't be entered by grim force.

Cheers,
Florian