I think a bit power issue, a bit driver issue, and much of the lack of my experience on multiple instance running.
Um, yeah, we can’t all be this guy:
HT is definitely the premier example of using multiple Renoises 
Second: how can I use the same controller for opposite functionality in both instances?
I guess it boils down to personal preference and doing lots of experimentation to figure out what really works. I did a small example on how to launch Renoise with different configurations:
https://forum.renoise.com/t/multiple-renoise-instance-with-different-preferences-setup/44153
It’s a start, but I suspect the rabbit hole could go a lot deeper than that…