I say skip the rear support. I fly without it, had motor troubles with the support in. Did a small poll in the pattern forum, not terribly definitive but my conclusion is the rear support causes more problems than it's worth (there have been more than the fair share of motor failures in this plane). Bearing adds resistance/friction, and rear support introduces increased side loads on the motor, if it's actually preventing it from flexing. The motor plate in the plane is fairly robust and I don't see any issue with running without the rear plate.

I had screws coming loose that held the rear plate in. Tried gluing the threads, still losing screws. This tells me there was unnecessary vibration, and sure enough when the motor failed, it was accompanied by a flapping sound, and the rear support had broken apart.

Just my own personal thoughts, take them for what they are worth.

Sorry, didn't see your last post before I wrote this - still think it's unnecessary weight and friction, but I hope I'm wrong and it works well for you