Jim, SampleTank is not designed to be a universal MIDI instrument player. Only a GM (General MIDI) synth is a universal MIDI instrument player. Anything other a GM synth requires very similar setups as SampleTank. If you want really good MIDI sounds you have to dig down and learn MIDI.

Also it you are going to use a non-universal MIDI instrument player you should not use it in BiaB (this is my opinion only) and use it in a DAW. BiaB is a PITA when it comes to non-universal MIDI instrument players, but I will justify that by saying BiaB was not designed that way. It is designed for GM synths and I think they added SamplTank to help people move away from GM, at least those of us who use MIDI and/or want to learn MIDI.

This is just my opinion and yours may vary.

Doc-take it easy John this is just a sharp scalpel. It will not cut deep so don't worry.
Me-I'm not John
Doc-I know, I am!

64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware