I try, I try.

while I was looking for relevant info for this, I got stuck on a thread about a very highly built civic. It was basically a full out drag car that the guy drove everywhere. His custom manifold didn't allow for a "real" IACV, so he ended up fabricating a mount so he could mount the IACV on the firewall, and then ran a small hose from the intake tube, through the IACV and back to a nipple just behind the throttle plate. Forget the exact set up, I know it wasn't stock since he was using some aftermarket ecu set up. He needed it because his cams where pretty aggressive and made idle difficult to maintain.
but for what you have going on, that might just be the best bet since you're idle will be pretty smooth, you should just have some extra load from the supercharger drag. Of which, How much added drag will there actually be at idle? How a supercharger behaves at idle isn't something I've ever put any thought into. It won't be making boost at idle will it? I'm assuming the supercharger would know when the throttle plate is closed. I know old school superchargers boosted if they were spinning pretty much regardless of anything else.