Hi there! Sorry for taking so long to respond, personally have been quite busy recently! Glad to hear you're interested in picking up mksc
When you said SC pros, did you mean for Shortcut, or Super Circuit? Because we have both non-sc and sc rankings on the site, so I think that's why chrono (guy currently using name vladimir putin) directed you to the SC section of my videos site, if that's what you meant.
If you're interested in the non-sc rules, they can be found here:
http://www.mariokart64.com/mksc/rules.phpand if you feel like chatting to the rest of us active mksc players (chrono has been very kind replying while the rest of us have been rubbish and haven't, but as he says himself, he doesn't really play the game), we generally are far far more active in our discord channel rather than the forum, which I can invite you to if you like. We are very welcoming to new players, and it's way easier to answer any questions you might having on the driving mechanics of the game, how to improve, what strats to use and whatnot on the fly.
Hope that's good for now, sorry again for taking so long to reply! Any more questions, please ask away