Adding a MCBR now would kill the ride completely, if you look at real B&M inverts, then there should be at least one more element (and maybe a few turns) before thinking about a brake.
But then again, a lot of newer designs that are about the same size as your coaster (like: Silver Bullet, Patriot, Phaethon, etc.) operate fine without one, just be sure to tweak the timing in the station so that it won't stack with 2 trains...
It looks really nice!! One question though, hand or computer made??