John,

I finally got around to trying out Halion today, using BIAB 2019 (622), Win 10, here are some details.

Initially, I installed CUbase LE, and Halion is included with it. The plugin showed up in the following directory:
C:\Program Files\Common Files\Steinberg\Shared Components\HALion Sonic SE\HALion Sonic SE.dll

For the default Synth in BIAB, I pointed it to that location, but it wouldn't recognize it as a valid plugin in the 64-bit BIAB 2019. Yet it was working in Cubase. So I tried downloading the free version in the link, it's HALion Sonic SE 3.2.15

It updated the .dll file at that location, and it was then recognized as a valid plugin. Tested it with a number of MIDI files, and it's working great. I noticed a better sound especially on the pianos. Also found that it works solidly with Reaper.

I didn't know about the "GM mode" either, thanks for the heads up on that one!

Jerry
2019 BiaB Megapack (634), RB 2019 (Build 4)
Reaper 5.983 x64, Audient id14 USB interface, Voicemeeter Potato 3.0.0.8, Nektar LX49+, Roland E20
i7-6700K Skylake desktop, 64bit Win10 Pro(1903), 32GB ram, 512GB system SSD + 2TB data SSD