You answered your own question. We have to wait until Pro Days.
Correction: Responsible fans (with little to no film) should wait for the evaluations of Pro Days and team workouts before attempting to draw anything near a conclusion, especially where linemen are concerned.
What we also need to do is sit back and watch who they invite in. DG and his team have done a wonderful job at evaluating talent and bringing them in. Outside of injuries most of our draft picks have been solid from DG. No true busts, yet.
This year DG will not allow OT go unaddressed. I think Oher will be a Panther and a 2-5 Round OT will be brought in to be a backup and fine tune his craft.