Picking how many formations to practice is no where near implementing anybody's full plan. It is good advice, though.
As far as the attributes for an OL, I have three sets of ratings I use, one for run blocking OL, one for pass blocking OL, and one that includes both.
The one that includes both is the hardest to get, because everyone looks for high numbers in all the relevant skills, At D-III that is what you need to look for, because no matter how you game plan, you are going to pass at least 20% of the time, even if you want to run all the time. At higher levels, you can choose which players are in for which situation, and you can recruit for run blockers and pass blockers, and the specialists are usually easier to recruit. Their GUESS and WIS ratings are lower, and more coaches will pass them by,
I will always try to get the combo guys, but if I can't I look for the specialists.