@Christoph-Hart OK, so if I put this onInit in the main script, will it do the job, or it needs to be put in each sampler?
Sampler.setUseStaticMatrix(1);
Probably need to pull in all of the samplers in an array and apply the script function to each?
I guess this explains why some samplers were mysteriously set to stereo and unable to be routed to multi-out in my compiled plugins when I was sure I set them all properly.