How does one go about setting up a recording session with Alc?
Give him a shout on Twitter and see what happens. For the most part, he only records for people he knows, then sends the sessions to Eddie Sancho for a tighter mix. Even in the Rick Ross/ALC studio footage, that's at ALC's house in Cali. He has a penthouse in NYC too where you can see a lot of Mobb records being recorded at on youtube, back when he was fukking with the ASR-10 real heavy.
He had that contest recently where he picked a favorite verse where people rapped on one of his beats and the winner got a single from him to be released through Decon.
The honest best way to get sessions/beats from producers you like besides paying them large amounts of cash is to make dope music and have them hear it and like it. Then someone will reach out to you, and it's easier to move into the "in-crowd" circle. Obviously this is easier said than done, much easier said than done, but lots of people have done it.
How often do you see threads about "why does x, y, and z producer work so much with garbage rappers?" That's one of the reasons why you you get albums like Group Home's Living Proof.
Or just be good at networking. If you really want to work with ALC specifically he's always said he prefers to make music with people he gets along with when there's no music talk involved at all. Network it up, man. Go out to shows, meet people, try to link up with like-minded indviduals and build.