Hardware Inserts on PT 9

[Obe1]

Well the answer is prob the same for most versions of PT, but I've never used hardware processors before and am having some trouble.

I'm using a Focusrite Saffire interface with PT 9, and am trying to figure out how to configure hardware inserts. I think I've got most everything set up right, my question is, let's say I have a single channel compressor plugged into analog output 3, and back into analog input three (as the PT manual says to do), is it necessary for the I/O inert page in PT to be setup as mono, or can it be set up as stereo although channel 4 of the 3-4 isn't being used?

Theoretically you would think that even if it's set up as stereo that you would still get some kind of signal coming back into PT even though you're only using channel 3 (instead of 3 and 4 of the stereo pair of I/O's). But it doesn't. One might ask, "Why don't you just go into PT and set it as mono then and test it for yourself?" Well, I'm at work right now and impatient lol IF you're bored, humor me with some input! Thanks.

Chris