Let's talk about the quarterback vision in the mesh and one of the reasons it's hard to run the triple to a three or two technique if you can't get movement. We like most people will combo the three technique, however that allows for a free run at the quarterback or to the Alley by a deep MLBer. (fig 1)
Many times we knock the quarterback for a bad read however without vertical movement he cannot see the key if he sits (Look at a past bowl game - I forgot the year - Georgia Tech played Iowa. The two linemen couldn't be pushed back and as a result the read key just sat in essence becoming a two assignment (dive and QB) player. ) Additionally. without movement, fullback must flatten out - (fig 4) not allowing him the vertical speed he needs to run by a sitter and break the arm tackles.
So its important if to plan on running the triple to a three tech or two tech to evaluate the matchup and be ready to abandon the play if you cannot get vertical movement. You must also be ready to evaluate and abandon during the game.
Also in evaluating results and grading be gentle on the quarterback who can't see his read.
A secondary answer
One thing that we've come up with over the years is to combine the loop scheme with the zone dive. WE simply call it "41 at the 3." The quarterback will run the triple to the widest technique - either the three of the two. We add to his read process the following - "Give unless the read key makes a direct path in front of the fullback. If you lose vision on the read key give."
If the quarterback loses vision of the three technique it means the three technique is playing up and out. We teach the fullback to run it like the zone read if he gets the ball. which would facilitate an a-gap cut. Since we are singling the three technique we are in essence inviting this. (Fig 5 and 6)
Note: the tackle will loop even with the Guard covered
We haven't done this much but it has served well when we have.
Hope this helps