I figured doubling my rooks on the c file is classical Sicilian play
20. Bd4b6 e5
I hated to play this, but the more desirable d5 is out of the game. It frees up my light squared bishop, but also fixes d6 as a target. Probably not my best move.
21. Nb3d2 Rc4b4 22. Nd2b3 Rb4c4
glad he accepted my offer, being 400+ points above me and a solid master strength player.