Quote:

...you can think of each gap as a restrictor, or orifice. the 2nd needs to be larger than the first to keep presssure buildup down.


I still don't understand why it would behave any differently with a bigger 2nd gap than a same-size 2nd gap... If the second gap is the same size as the first, then the pressure will escape just as quickly as the first gap can let it in.

The first gap is the initial restrictor; as long as the second gap is at least as big as the first, there shouldn't be any pressure build-up. If there is, then something else is going on that's not being taken into account by simple ring gap math comparisons, such as additional blow-by getting past the ring-to-cylinder contact area, in addition to what would be expected to get through the ring gap.