Sounds like you are coming up with your owm DIY version of a HH SuperShelter. Which has always worked pretty darn good for me.
What kind of space blanket are you using at 10 oz? Mine all weigh 2-3 oz.
That HH OCF pad does a great job for me ( and Newt!
) hanging under the hammock with an UC under it and a 3 oz space blanket on top of it. The HH UC is tensioned just right to hold the pad just snug enough against the hammock without really much depending on the suspension. But down or especially fleece jackets and many other things also work well down in that UC, either to boost the OCF pad or just by themselves. Just have to be careful with down, the UC tension tends to compress it in spots.