BTW, one thing to remember in college (and NFL) as I believe E'Tough has mentioned, the rotation of OLs is much, much less than DL.

Six OLs might play the five positions while a total of say EIGHT DLs might play the four positions during a game.

Baring injury don't need as much depth on the OL as the DL.

So 2-deeps on the OL is not equivalent to 2-deeps on the DL.