1. First, 75 thresh was way too high (in hindsight, the original 50 was too high as well) last year....made linemen too fast relative to the backs and de-synced the run game (in addition to causing QB AI issues). I tested thresh extensively this year and based on what I observed, it's my opinion that Thresh should be no higher than 52 unless you are willing to modify gameplay sliders.
2. I have not tested this type of approach this year so I will not comment.
3. Neither approach is "better" - I recommend following the lead of whoever's slider set you are using.
Edit: as a side-note....I don't feel that I am quite done yet with thresh...the more of a feel I get for the game, the more the little imperfections are standing out.