I have no idea how you scout offensive line prospects at this point. As you said, any kid worth a top end power 5. Offer is going to be so physically different from anyone he plays, and most of these camps are glorified seven on seven. Sadly it's been over a decade, but my wife's cousin was on the Pennsylvania state championship team at the highest level, and they had an offensive lineman who was a 4* prospect. He wound up going to Michigan, and I went to see them play maybe three or four times that year. My takeaway was that he was just big. He pancaked his guy most of the time, but I felt like if he was going to be an impact player at the Big Ten level, he should be able to take these 215 lb defensive lineman, knock them over, and get to the second level. I almost never saw him do that. He would regularly flatten whatever defensive lineman was across from him, but he would go down with them. He is the only power five level offensive lineman I have seen play in high school
It's interesting becuase you have a few types:
-Kid who is big, fast, kills it. That's what you want, but has most of the questions everyone else does. Has he tapped out his potential? How will it look against better guys? Is he gonna react the right way when a senior just whips is ass in Oklahoma drill for a while period
-Kid who is big, fast and isn't good enough. I lived near a town with a mid-range P5 recruit maybe 10 years ago. He was big and had good feet. He was also soft and didn't dominate much worse competition. A bunch of mid-range P5s were on him because they figured maybe they could coach him up to use the tools
-Small, high-upside guys. Wisconsin did a lot of damage with these. 250 pounders with the right frame. Again, that's about projection and development, but if you get the right dude with the right attitude, it comes together.
-Dudes you just get and hope for the best. Sometimes you take a guy because he's not too small and you need someone, and he just does the job.
The bust rate is of course high, and it's just a position where you never have enough skilled dudes. O Lines are like OCs, most folks are never really happy with them.