I’ve read a few threads that indirectly address the question but can’t determine which is best.
I’m combining a couple libraries and plan on doing some ‘mixing’ in VEPro. I read something that indicated multiple instances may complicate this? I’m also wondering about performance since there are settings to give each instance a particular number of threads. Or does it even matter?
I wouldn’t worry about using multiple instances, it should be fine, although it may be somewhat dependent on your computer specs. If you are bringing each instrument into the Dorico mixer on a separate audio channel I would recommend sticking with just Port 1, midi channels 1-16. For your next 16 instruments use another instance, also just Port 1. If you bring an instance into Dorico via the VEPro stereo bus, then using multiple ports (each having 16 midi channels) is okay and you can get away with having just one instance with many instruments. I personally find it easier to manage my template with multiple instances: One each for strings, brass, WW etc…
I prefer the VEPro mixer so I use a single instance for everything because there is no way to mix multiple instances together in VEPro. With the ability of the VST3 to use multiple MIDI ports I can have up to 256 MIDI channels which is enough for me.
The main reason that I bring everything into the Dorico mixer on separate channels from VEPRO is to make use of the solo command in Dorico. I use solo and unmute via separate key commands in Dorico which is very useful. Yes, you can select an instrument or multiple instruments in Dorico by highlighting the staves and hear only those staves which are selected, but it gets a bit tedious if you are going back and forth on a passage because you can easily lose your selection and have to reselect everything. If everything comes into Dorico as a stereo feed, you can only properly solo things directly in VEPro which is more fiddly, especially if you’re scrolling through 256 instruments!