The Nemo Zor Short weighs 9.1oz (at least mine does). Add a trimmed-down 1/8" thinlight pad for a couple ounces and use your Murmur pad for the thighs/legs, along with any extra stuff/pack for your feet (all under the 1/8" pad). Should drop some weight there, plus you have insurance in case your pad pops.
I've found the dropoff from a short 2.5" airmat to be quite uncomfortable, but some people can do it. Also, a short pad means anything under your legs/feet will migrate throughout the night. The 1/8" pad will keep this from happening (it's very grippy).
The Zor Short with the thinlight will be around 12oz at most. I've used this setup with a quilt before and it works fine. I actually use a trimmed full-length 1/8" Evarest (3oz), but they're out of stock right now. Keep in mind we're only talking about losing a few ounces for a possible change in how you sleep, so it may not be worth it for you. I've found it to be extremely comfortable, though - moreso than a NeoAir. Never tried a SynMat.