Tough call, but I will wade in with a prediction that may very well make an arse of me (I can take it!).
I predict that the mixture of the tube pre and the Class A Rawson will do it for you. I have had Class A SS before (Sugden) and I have owned decent gainclones, and I would take the Class A myself.
I know that the chip amps that you have are better than what I had, but I bet the wetness of the Class A thing will please you.
Can you try it with the SB direct to the amps too, just for kicks?