I am becoming increasingly frustrated trying to find ideal sleeping pads for winter use.

Self-inflating mats like the Prolite are prone to the internal foam delaminating from the cover fabric and turning into a big bubble. A shame, because they are the most comfortable in my opinion. Are self-inflating mats that do not have vertical punchouts in the foam still subject to this problem? I was thinking about one of these two options:
* Exped SIM Comfort Duo 7.5 (R-value of 6.4)
* 2x Nemo Tuo 25L (R-value of approximately 7.0)

Both of those options are quite heavy though at 7.5 pounds. Another consideration, though it is not sold in the USA so I'd have to jump through some hoops to get my hands on one, would be the Exped SIM Comfort Duo 5 (R-value of 4.6, weight of 5.25 pounds). Maybe not warm enough? The nice thing about the Nemo pads is that they would have redundancy if punctured.

Blow-up mats are much more failure prone, with baffle failure, perforation development, valve failure, etc.

Any sort of inflatable pad is prone to puncture, and some sort of failure seems inevitable after regular use for a while. I'd really prefer something foolproof. I also need something that will work in 0 degree temperatures. I also need wide pads of 25" width, to accommodate a 50" wide quilt.

We are plenty comfortable using short RidgeRest Classic pads in the summer, and it is nice knowing that they will never fail. The problem with closed cell pads is twofold:
1. Not a high enough R-value
2. Very bulky

The bulk is not so bad with short 20" wide SOLite pads - but with full-length 25" wide thicker Solar pads, it's significant. I am not sure how to reasonably carry two of these without them becoming a big nuisance. Or worse, 4 of the dang things in the winter to get enough warmth. On the other hand, they are not heavy, so maybe I can manage to strap them on to my pack somehow. Do people generally strap these outside of their rain covers (that's what I did with our short ones), or use larger rain covers which will contain the strapped-on pads?

I found a Hyalite Classic CC pad which claims to have an R-value of 4.0 while being thinner than either of the RidgeRest models, so that would solve some of the bulk problem. Problem is, it is not available in a 25" width (and even the regular size is out of stock). Maybe there is somewhere I can order a basic flat CCF pad in a large size? Maybe even some option for different thicknesses / R-values?

How much R-value do you really need in cold-weather camping? Does anyone use CCF pads exclusively in the winter? Will a RidgeRest Solar (R-value of 3.5) work alright if a very warm quilt is used on top? Does insulation under the legs matter as much or could I combine full-length pads with torso-length second layer pads? Two large RidgeRest Solar pads weigh 3.25 pounds which is half the weight (but also half the R-value) of the self-inflating options mentioned above.

Another thought - what if I sewed a 1.1oz sil-nylon slipcover for the RidgeRest, which would trap air into its pockets...would this increase it's R-value?

Or do I give up, and because they are light, carry noisy XTherm MAX pads, and include an extra one since they are light enough, for the inevitable time when one gets punctured and I can't manage to get the patch right in the field in the cold right away.