Then why 2 since 3 is better ? :)
My 5 is an educated guess just like your 2.
NT tournaments are very different competitions and yes, low handling doesn't impede success if primaries are high relatively, even in U21. It's different from a league, especially at a level like US D.IV where you need to find an effective balance under economical restraint.
Finally every skill increases number of scored points by own team or decreases number of points scored by opponent.
Probably. Now measuring the effect of each skill when some probably work in group is a more difficult problem to solve than your calculation make it look.