Hi there,
To address your specific question about "scribbling a lot of stuff." It depends what you mean by "stuff"!

Using the scratch pad to break down RC and CR passages in an effective manner is an absolute NECESSITY when it comes to conquering those two Q-types. But obviously not all notes are of equal value. If you're summarizing all the details in an RC paragraph, that's a massive waste of time. If you're writing down the function of every paragraph and the author's point of view, that's a really smart use of scratch paper. Regarding the "T" method, if this works for you and allows you to get 90% or more CR questions correct when you work untimed, then you should definitely keep using it, and do regular pacing drills so you can gradually shave down the time it takes you to put this strategy into action. If you can get your CR done in under 2 minutes, you're in good shape, but don't jump straight there. Maybe start with 4 minutes a question, then 3.5 min, then 3 min, then 2.5 min, etc. Shave off seconds once you've been able to master high accuracy at the previous benchmark. But be accurate FIRST.
When you do practice problems, it's fine to do the lionshare on plain notebook paper, but when you do practice CATs, I'd highly recommend buying a laminated yellow pad so that you get used to using it BEFORE Test Day. It's a little weird at first. You can buy one used on Amazon for $10-15, and I definitely think it's worth it, if only for the psychological benefit.
https://www.amazon.com/Manhattan-GMAT-Si ... 0979017580
Good luck!
Best,
Vivian