I have a few different sizes of single layer bubble foil insulation I use, and it's tough stuff.
The smaller piece is 25" x 40" and weighs 4-5 ounces. I use it under my sleeping bag with a visqueen groundsheet and with or without a visqueen tarp.
The other bubble foil piece is used as the floor of my tent, no other groundsheet is used. It's pretty big, 40" x 80". It packs down to about a 6" diameter by 20" wide roll and weighs about 12 ounces.
Folded up, either of these pieces make a great sitting pad too.
Also I was wondering if someone could tell me if the E-blanket could possibly be reflecting any radiant heat back at us as that may be somewhat useful information.
Well you hooked me with that bait...
I've tested various reflective materials a lot for several years now in cold weather and, yes, the reflective surface absolutely does reflect your body heat back into your sleeping bag and tent. The tent I use is made out of SOL Emergency Blankets. Most of my nights are spent in below 40º, many of them in the 20ºs, and they're long nights, so I'm a big fan of the stuff. A small campfire will warm the inside of the tent to +80º in almost no time and a good bed of coals will keep warming it for hours after the fire has died out.
The key to using these reflective materials is to make sure there is air space between you and the material. This makes the bubble foil great for sitting pads and ground cloths, and the SOL Emergency blanket material works good for "Super Shelter" or "Campfire Tent" designs. The tent I made is a small version of a "Baker's Tent".
So, just laying an emergency blanket under and over your sleeping bag will keep you warmer, but it will also gather condensation. My tests in below 20º left a very small coating of frost on the outside top of my down bag, but I did not get wet from it. In 40º weather that might not be the case, the bag probably would get wet in humid conditions, but I wouldn't use it in 40º weather.
I encourage you to experiment with these materials. If you can have campfire where you'll be camping then make a tent or super shelter and test it out. It doesn't cost much and it's a good excuse to get out there and I'd like to hear about how it works for you. I'll be using the one I made soon here (our backpacking season start in about two weeks!)
Here's an old post about the tent I made. There are lot's of videos about "Super Shelters" on YouTube, but I honestly think the "Baker's Tent" design I copied was worth the extra effort and probably works quite a bit better at retaining heat than those you'll see on YouTube.
I also think that much better designs than mine can and should be made. I'm lazy, and I like my tent, so it might be awhile before I make another. But I won't go back now. That tent works so good here, where I backpack, that when it wears out I will make another. I'm thinking a half tube or half dome design might be cool