I think I can answer a few of the questions here.
With TA31, you will not need a cheek piece for the carrying handle, it mounts directly to the handle with one or two screws.
TA31 is like a TA01 with a Optima, the BAC works just like a red dot, Ithink mount a Optima to it would be a wate of money.
I don't see much point to a Tri-Power, but it is suppose to new and a hot item once it hit the market. The prototype I saw I wasn't that impressed with it.
For a weekend shooter, iron would be fine, if you are looking for added precision and you don't want to spend too much, you should look into a IOR M2, or a Weaver 4X, or something similar. It is not an ACOG, but it is half of the price. But if you want the best CQB-300+m optic on your weekend, save you money and buy a TA31.
Hope this helps.