re: the size differential in the trenches.

I think you might be overthinking this weight thing. There will be a lot of other facts at play here. Example--the following is from the Oregon paper Registar-Guard a couple of days ago:

"Offensive line coach Steve Greatwood answered one of Oregon’s biggest questions entering the 2011 season when he said after Thursday’s final workout of fall camp that redshirt freshman Hroniss Grasu had won the job to start at center.

Grasu will have to do it against a stout defensive front from the mighty Southeastern Conference
It’s a daunting challenge for anyone — and especially so for a redshirt freshman who has never played a down of college football"

This could be a very long night for Mr. Grasu, me thinks. I'm sure the D-line will be licking their chops!!