I was running a Wix version of the FL1A. Now since I have so much crap under the hood with the supercharger coolant bottle and pump, the vacuum canister, both oil catch cans, I have the trans filter mounted on the cross brace near the brake booster so I run the Wix 51516. I just throw a zip lock bag under/on it and unscrew it when its time to change. Prefill a new one and let her rip...
Keep in mind, I'm not running a bypass like you are, just in series. I tapped (cut and flared the ends) into the line when it comes out of the radiator, and before the cooler built into the condenser. That way the fluid is a little warmer before filtering. I don't know if that's good or bad, but it works for me.