Best replacement pistons for stock '69 engine

The KB pistons will end up with too much compression for what "you" are wanting to do. If it was my build, I would stick with something simple and stock compression is simple. You've already said you don't want premium gas involved. So don't even look at the KB pistons. You shouldn't have even mentioned them. Now you're going to have certain members on here trying to railroad you into using them at the cost of you wanting to keep it simple. KEEP it simple. It's your money. Don't let it get "unsimple" unless you decide that's how you want it.