I've only used an SF2 with FDVs, and the SF2 was louder. I ended up wiring the SF2 in parallel, with the FDVs in series to help balance the output (but have since switched to all FDVs).Can you mix one Super Fatty II with two FD3s? I mean, I know you CAN, but is it something that might work, or is it best to stay with three of one or three of the other?
What concerns me would be more windings in the SFII would overpower the other two FD3s.