As I was averaging out the teams size in the five big D1 conferences (SEC, PAC12, ACC, BIG12, BIG10), I noticed that there was a pattern.
Almost every school's average height and weight is identical - give or take an inch and 5 lbs.
As you can see the heaviest conference is the SEC and the tallest is the BIG12.
I wouldn't say either has an advantage, those are just the numbers.
What I really want to show you is the size difference between the four college divisions. I took the top 10 teams (as of week 7) from each level and averaged their size.
College Division Size Comparision Chart
You can see below that the average D1 offensive lineman is 22 lbs heavier and 3 inches taller than the average D3 offensive lineman.
That is quite a spread. And remember this is an average of all offensive lineman. Freshman through fifth year seniors.
Now get out there and win every block.