This new pad from Klymit is definitely worth a look if you are planning on some hammock camping, hunting or fishing: https://www.klymit.com/hammock-v-1.html. Its design tackles the single biggest issue of hammock camping head on, ie how to keep your back, shoulders, elbows, arms & knees comfy and warm.
I find any insulated rectangular pad big enough to keep me warm, but if you are any wider than me, you might want a wider pad (as I have mentioned in earlier posts) or some ‘wings’ to warm up your arms etc where the sleeping bag’s insulation will be compressed against the hammock. Mind you at an R rating of 1.6 this pad would only keep you warm enough in summerish weather – though your sleeping bag insulation would drape into its valleys and add somewhat to its insulative ability.
Speer Hammocks used to make a Segmented Pad Extender which kept your arms and shoulder nice and warm. We made one of these too and it worked well. Here’s a link to making one yourself: http://www.tothewoods.net/HomemadeGearSPE.html
I recently posted a number of other hammock items you might also find of interest: http://www.theultralighthiker.com/hammock-camping-double-bunking/ & http://www.theultralighthiker.com/make-your-own-tarp-or-hammock/ & http://www.theultralighthiker.com/hammock-hunting-till-dark/