If you're waiting in C-Pool you will be API complete and know what aircraft you will fly in Primary (unless something drastic happens). There are different survival requirements for the T-34 and the T-6 (ejection seat vs bailout, koch fittings vs unstrapping harness). At that point, you'll know what you're flying and can start studying. I would recommend getting ahold of a Natops and PCL. You can study systems (and everything else) in the Natops and use the PCL for Checklists and EP's. You don't need to sit through systems class to get a basic understanding of what "PCL-IDLE" or "Emergency fuel Shutoff handle-Pull" means. The sooner you can rattle that stuff off, the easier the firehose will be when they front load you with info.
I'm that guy.