Advice for a 11B wanting to go 35

I'll give you the talk that everyone looking at MI should get, but don't. First of all, take a serious look at other services. If you have a degree, look at the Coast Guard Direct Commission Intelligence Officer program. On average, you'll have a better experience in the intel field in any service other than the army. That's not to say you can't land in a great assignment in the army. I won't harp on it much more, but at least consider another branch. Your medical issues might pose a problem with that, but it's worth a look. If you solely want career progression, but don't mind miserable work (imo), 35F is a good option. 35M is very hit or miss depending on your own ability, unit, and some luck. Career progression was great during GWOT, then came to a grinding halt until fairly recently where it has normalized somewhat. 35P can be a very rewarding job, but career progression is historically terrible or non-existent. 35N can be good both career-wise and work-wise, but job satisfaction is going to be heavily assignment dependent. 35S is similar to P and N, but poor career progression.

35N 35S and being a good 35P require a great deal of technical aptitude. 35M requires you to be good at talking to people, but moreso good at listening to people. Successful ones are typically extroverted, but you can be introverted and be great if you're intelligent enough to to effectively listen to and communicate with people.

35L is similar to 35M as far as aptitude needed to be successful. Present day, most 35L assignments are probably better than your average 35M assignment, and I'd lean that way. Probably wouldn't have given the same answer 10 years ago.
35T is an IT guy with a clearance. 35Gs have some really cool assignments, imo, but I can't speak much to job satisfaction etc. You could be in a BCT printing out maps (like a 12Y), or working in way cooler assignments.