Get yourself a xicoy LGC15 and solve your braking. Had relatively the same issues. Went thru 3 other controllers before the LGC 15. It has a gyro and if the plane starts going to the side, it lets off on the offending brake and also uses the nose wheel to also correct. It takes a bit of programming. But, It solve my brake problems even in my very light Ultra Flash. Make sure you get one that is either for your retracts or an open programming one so you can tailor it to your specific retracts. I got my open programming ones from PacificRC.