The real answer to your question is to have PGMusic incorporate all of the stand-a-lone functions into the VST. That not only would solve the problem but also allow the PC and MAC versions to be announce and delivered simultaneously. But until that time I use my Studio One Pro 6 and BiaB separately. YMMV
PS I know you don't use the VST and the above doesn't answer your question.
The problem with running them separately is that you can't play them simultaneously.
For example, if you press Play in STUDIO ONE, a separate BIAB application won't play.
So sometimes it's not possible to demonstrate something.
However, since BIAB has made a separate VST, I don't think it is possible to open the main BIAB program in VST mode. As a result, BIAB separately designed the new BIAB VST
The problem is that DAW doesn't necessarily collapse anytime soon, and that hasn't changed. Therefore, I do not use BIAB VST