I hear you about the hassle of multiple foam pads. I remember snow camping once with two Torsolights, and I woke up every hour or so with a cold bottom whenever the two pads slid apart from one another. This still occasionally happens when I use a thinlight folded up for my legs.
I have, however, found that a foam pad stays put if placed on an inflatable. In fact, putting the Thinlight under my inflatables really keeps them in place, and acts as a sort of glue adhering the inflatable to the groundsheet. Placing the thinlight above the pad also sticks remarkably well; I can shift from my back to my side without movement, as the friction between them really keeps things in place. I really like how grippy too GG foam is! But it seems to be much more grippy with the full weight of my torso, while it still slides around under my legs (or maybe I just kick a lot in my sleep!)
I think I would try to find away to attach the 1/8" and 1/4" pieces so that it makes one long full-length pad, to which I place the torso pad on top. Of course, if I were truly thinking about a viable option if the pad bursts, then I should be thinking about carrying a full-length 1/4" pad. But that sounds so bulky! At least the inflatable would pack smaller without the insulation.
Something else I just realized--the slightest Clearview pad is 11oz, but it's 60" long! So I could get a longer pad (aka more comfort) for lighter weight than my 47" pads (including the Thermo 2/3). Since the GG pads are all 60", these would pair quire well. Now it's just making the decision between two 1/8" Thinlights or one 1/4" Thinlight. one advantage of two 1/8" pads: they would pack easier; two rolled up side by side could fit in a side pocket. I've never liked wrapping my pads around my gear in my bag, because then I can't pull the pad out for my lunch break without completely unpacking my bag!
I usually don't need a pad for my feet anyway, as I just double up my socks (I bring spares anyway), which adds an equivalent amount of insulation. And if it does get cold, it's not to hard to curl up a bit on a 60" pad.
I also just noticed that the non-insulated Ether Thermo 2/3 is 3oz lighter than the insulated version. If I decide the Clearview is not sturdy enough, I could compromise with the non-insulated Ether and still save a few ounces. Still, 60" and even lighter makes the Clearview quite tempting!