Welp, before the Charge Filter arrived I picked up some 700x23 tires for my 29er MTB (full XT drivetrain & hydro discs) to see what triple-digit tire pressures are like, and get some practice mounting them (for the inevitable roadside flat repairs). Rode the MTB that way for a few weeks, and it worked better than I expected. When the Filter came in I rode it about 40 miles using my own wheels/tires/seatpost/saddle so that (1) I'd have a closer comparison between the two, and (b) I would avoid putting visible wear on the Filter, in case I decided against it.

Which I did. If the MTB hadn't done so surprisingly well, or if I didn't already have it, I would have been very happy with the Filter. But it's hard for me to spend whole-nother-bike money on something that isn't significantly better than something I already have. (Also, I wasn't a fan of the amount of lever travel required to row multiple gears with the SRAM Double Tap.)

So, all that wondering aloud only to find out I apparently had what I needed all along! Looks like y'all were right.

T'was dead sexy in black with white slicks, though: