.....could you tweak the sheaths to adjust to fit the different handle sizes? .......
Nothing is impossible but I think you'd be messing with the single most fussy part of a Kydex sheath and the simplicity that makes them affordable. Getting the tension just right so that you retain the knife without wedging the blade itself between two layers of Kydex, yet have smooth insertion and presentation is pretty much what forming the sheath to the single specific knife is all about. I am just a beginner with this stuff so someone more experienced could tell you I'm full of beans.
I would think that you would be better served with two sheaths and using .060" on the one for the wrapped handle. Not saying it isn't possible but it would take some fussing and the probablility that you are not happy with it using one knife or the other would be high. You could also forget to tighten the screws on the "naked" days and lose your prized possession.

The screws on the highly contoured sheath I did only attach the sheath to the Tek-Lok. The tension is all in the forming and the placement of the rivets. That is why the top rivet (aka "mounting hole") only goes through the back of the sheath. If it went through both layers, your knife would be almost permenently locked into the sheath.
On the other hand, if you saw my "neck sheath" for my "naked" PSK, I am holding onto the the front edge of the roach belly(?) with the Kydex and the sheath should not be in the way of the wrap. Shoving the wrap in and out of the thicker Kydex would probably loosen the warp up anyway. If you latch onto this part of the blade, you have to ease and polish the edges on the knife so you don't shave away the little bit of Kydex that is holding onto your knife.
Blah, blah, blah... Man, for someone who doesn't know what he's talking about I sure have a lot to say, don't I? If I didn't answer your question, hit me up again.