I see, thanks for clarifying. Yes, I was suggesting using 2 FX Chains for your left and right signals.

All of the H9/H90 algorithms are fully compatible for mono/stereo inputs and outputs. The algorithm will process in mono if only 1 input/output is connected, or stereo if both inputs/outputs are connected. For mono in / stereo out or stereo in / mono out, the algorithm will mult the signal or sum to mono if necessary.

This is not the case for the older H8000 algorithms. Some of them may always sum to mono, some will be stereo etc. depending on the algorithm.