Forgive the stupid stroker kit question.

I read that question as asking about the kit parts, not the block prep...
In both cases though its subjective by the builder (or assembler). I won't let anyone balance my stuff aside from "my guy". I have found some aftermarket rods when cycled, lubed properly, and torqued properly need to be resized... That is to say the bores were not round once that was all done, because the manufacturers don't always do all that before they finish machine them. The cranks are all pretty good. Some will have a little taper, better ones will be "better". Most stuff will work. But some people are more picky and normally that "picky" will be rewarded by more power, longer life, and better quality of life.