@ceylonfj40nut ive actually relocated my one way valve up to my core support area and have been meaning to finish my EVAP system but ive not gotten around to it. I posted this to your thread.
Im adding a square OEM GM charcoal canister to mine back near the fuel tank. The inlet will go to to the in on the canister, the outlet will connect to the existing hard line that goes up the frame to the engine bay. on the other side of that, im going to connect a hose to the oem Purge solenoid on my intake. At least on Gen 3 you cant actually tune that out of the softare, you just disable the MIL Light. Should still purge it like normal.
The charcoal canister i am using is GM 215-180