1
was always considered key, in the articles I looked at prior to the 3-parter here... so much so that one medical study found that injuries increased as the mound got higher. (That would make sense in the reductio ad absurdum, that throwing 90 mph off a cliff would be more unnatural than throwing off flat ground. Nolan Ryan loved throwing off flat grass.)
That is the consensus Anon, definitely, that taller mounds (and longer skeletons) get more leverage to the pitcher...