Other that an underquilt which would be superior? I am curious about your experiences with alternative insulation for underneath. I see Tyvec and reflectix but wonder do they slide around or bundle up, are they comfortable to lay on? Share your stories.

ccf pad, not as comfortable, but only about $10. And light weight. Use an SPE to assure coverage of your sides and manage the separate pieces of foam.

I have a 3/4 length underquilt from Warbonnet. It works great down to about 35 degrees. I wish that I had purchased the full-length version.

quote toddhunter: "ccf pad, not as comfortable, but only about $10. And light weight. Use an SPE to assure coverage of your sides and manage the separate pieces of foam."

Yup. The SPE really makes a diff if you go the pad route. Otherwise you get COLD shoulders.
IF you can get your hands on a Big Agnes sleeping bag then use the pad pocket. Or if you have a double layer hammock put the pad between the layers.

I am currently using an ALPS pad that is 3 1/2 inches thick and plenty long and wide for my carcass. I was wondering about other things I might use to improve the barrier below.

Not clear what you want to improve. Comfort? Insulation? Weight/bulk? Weather protection? I have another weather/bug barrier, a dri ducks poncho mod that snugs up against the hammock. Some heat retention and waterproof/windproof.

toddhunter, actually okay with what I am using, curious about alternatives to pads and underquilts and what people's experience with these alternatives might be.
I got thinking about this with a reflectix comment in another post and what it would be like to lay on that in a hammock. Maybe okay on the ground, but hammock? So I posed the question.

My impression, having never used the reflectix for underside insul, is that it will work just fine. Hennessy uses it as the insulation in their Super Shelter. I don't think it is any less permeable than ccf, but maybe it weighs a bit less for the same temp rating?? Might be more slippery since it is mylar coated, but otherwise I think it should be plenty warm.

quote bhouse46: "toddhunter, actually okay with what I am using, curious about alternatives to pads and underquilts and what people's experience with these alternatives might be.
I got thinking about this with a reflectix comment in another post and what it would be like to lay on that in a hammock. Maybe okay on the ground, but hammock? So I posed the question."

Cool. I'm always looking for improvements. I couldn't find the reflectix when I looked at Home Depot, so stuck with the ccf. I also played with a mod of my down parka that worked pretty good. I just ran cord through the arms and attached them to the ends of the hammock. Kept me warm and comfortable one night. I may have attached the drawstring as well. I figured I could use it during the day too. It still seemed heavier than the ccf, and kind of bulky. Let us know if you find a better method.