What is the current theory behind piston ring location. I've noticed many off the shelf pistons are in the .150-.180 range on NA lightweight pistons. .2-.25 or so on street/strip pistons, an .3+ on forced induction pistons.

To run a small compression height, are small, .043 rings necessary? What is the spacing between 1&2 and 2&3? Are any gapless designs popular?

Thanks,

David