RE: Trimming for level flight?
Retrim as you fly, based on your needs.
In fact, once trimmed correctly, your re-trim will be a click or two not more, and that becomes subconscious and automatic with time.
It is mostly a matter of getting used to things basically, I am sure you won't worry about that in a couple of months.
I prefer to trim it level at 3/4 throttle for easier low passes.