Nighthawk,
You have brought up one of the dilemas that we face when we are making hunting ammo. I have always understood that setting the bullet into the lands will spike pressures and probably increase velocity, have never heard that seating deep will do that also. I would expect that seating deeper will give an almost Weatherby-like free-bore where the bullet has a little travel before being engraved in the rifling. There are guys who have much more understanding of internal ballistics and I would leave this discussion to them.
You also must remember that there seems to be some allowable lattitude in just how long each individual bullet can be. They just don't seem to be as uniform as we would expect so that makes uniform overall length a slightly tricky objective.
What you do bring up is the dilema of having a relatively short magazine well relative to how long you could or would like to seat your bullets. We can use the nifty Stoney Point OAL guages or whatever to get the bullets out to just "kiss the lands" but nine times out of ten that will result in the cartridge not fitting into the magazine. If we want to shoot single shots that is not a problem, but if we feel the need for fast repeats we usually have to shorten up our overall length.
I tend to load to the mag well length nowadays, just don't see the sense in not having ammo in the mags of my hunting rifles. We even do that with our steel clanging .308 Win. ammo - seems that 2.830" will fit in most mag wells.
Good question, I am looking forward to reading what some of the other fellows have to say.