I wouldn't recommend EPH for studying, its a good stim however it doesn't make you want to sit there and read, its like a very weak party drug, especially when mixed with booze. MPA, well, you would only need to dose once, well I do anyways, 50mgs up the nose and it will keep me awake and alert for a good 8 hours. The thing with MPA is yeah it'll allow you to sit there and study, type for ages etc.. But the stuff you're learning doesn't stick. You just end up learning a lot of things and then the next day forgetting most of it. To be honest its better suited if you need to write an essay where you already know the subject and you just need something to make you carry on typing.
I have yet to find a RC that helps me study whilst maintaining the information the next day.
I have no EXP with ritalin and any of the amps you get for ADD/ADHD but apparently they're very helpful with studying.
Hope this helps.