This is very interesting. 1. Would it be possible to extract the HOA signals and decode them in Metasound? Working out delay compensation would then be quite easy, having distances. and some form on input from BPs . It could be possible also to implement an ambisonic weight formula directly in MS maybe?
2. Are you using some form of convolution for speaker equalization? I ask because modifying the spectral characteristics would allow to import data of existing speakers for accurate simulation and auralization…