I have the "little brother", an RCF 732A, and it can definitely handle a low B nicely. Yes, it's heavier, at 39lb. Older setup was Shuttle 9.2 & Big Baby 2; I'd have gone back to that if I wasn't happy with the RCF.
Your Super Compact is a good cab - I haven't played one but I had the previous generation Compact. I don't think it's full-range though - I didn't love it for upright.