There are no stupid questions, except those unasked.
I have a Supershelter but am much more likely to save it for car-camping. I eschew single-use gear when on the trail. A lighter option is a mylar space blanket, slung under the hammock with elastic. It takes more effort, but I've done this for years. The space blanket can be taken off and used as a ground cloth should I have to (Horrors!) sleep on the ground or hung behind me to reflect a campfire, etc. I can lay my Gossamer Gear Thinlight pad on top of the space blanket (under the hammock) for some bottom insulation. I also may carry a fleece poncho/tunic that I sling under the hammock with elastic, as well. How may layers I need, of course, depends on the temperature. My issue with under quilts is that they are no good for ground sleeping insulation. I MAY make a synthetic underquilt that I can use as a tunic one of these days, if I can find suitable materials with some stretch. For this one, as much as I like down, I'd avoid it so I could wear the tunic under my pack. I suspect that down would not hold up well under pressure, sweat, and movement.
The open cell foam that is sold with the SuperShelter Undercover has heavy-duty elastic for longitudinal and side tie outs. If used properly, the foam should stay snug against the bottom of the hammock and move with the hammocker. I think Tom has a video on his website that explains how to set up the SuperShelter system. Customers always can call Hennessy Hammock with questions, or PM me and we can communicate off line. Send me a phone number and I will call to talk you through your set up.
Hennessy Hammock afficionado and supporter.