I'm waiting on a F1 for a 30cal can. Been pondering a 300 upper. Why not slap a 300 upper on one of your existing SBR's ? If you like it then F1 another lower.
Regarding what can, what have you road tested to make sure,that's the one for you. I have a 45 YHM Cobra, it sees most of it's time on my rossi 357. It may be a 45 can, to say I'm not impressed using it on a 45, is an understatement.