You can put SAFE into an AR636 if you install the version 2 code on the website and configure it using the new PC app. Details are in
https://www.rcgroups.com/forums/show...-another-plane
Rudder and aileron shouldn't be mixed in the transmitter.
I too love the Mini Apprentice. I've bought several of them for friends and family and always been happy. I even used the guts in a seaplane design, just moved everything over. The AR636 is much better than the EFL receiver.
Andy