I’ve rarely found it necessary to run an effects device with stereo inputs. Most will take a mono source and process it in stereo, so I only have the returns in stereo. In fact, I don’t have any effects possessors running with stereo inputs at this time. You might try it that way… one effect send for each processor. When dealing with ambient processing I don’t hear much difference as long as the stereo aspect is preserved in the dry signal, which it will be using a console.
Reverb, echo, chorusing, etc will take a mono input and give it the same width as if you used both inputs. Many outboard digital processors combine the right and left signals before the effect is applied anyway. Check the specs for your processors. Quite often the right/left inputs are provided for people using the processor without a console, so using the blend control one can preserve the a stereo source. Since the blend control should be all the way wet when using a console it probably doesn’t matter. Depending on the processor either the right or left input will be designated mono-in and sometimes either will do.
