...and that theory was based on what?

So here is what I'm thinking:

1) assuming that a wedge head is used, and therefore for a particular valve diameter size increasing the lift brings the valve closer to the cylinder wall, therefore shrouding the valve

2) but #1 above is certainly going to be impacted by the valve angle in the head (which is why I said "wedge" b/c a hemi chamber would certainly not follow these rules quite as readily I'm thinking)

Not saying this theory has no merit to it, but I'd like to understand what criteria it is based on.