I've been using a old Delsey Helium roll-aboard and it's finally starting to show its age. The unique tethered TSA pouch has detached, and a wheel jammed in the middle of a 7-city swing through Europe last week. The wheel is spinning again now, but I'm ready to invest in a new bag.

I'm 1K on United, and hence most of my international travel is on Star Alliance - United when possible, then Lufthansa, Air Canada (ugh), and occasionally others. My Delsey just fits into the United sizer (packed normally it's a snug fit), and it's never been questioned on any domestic or international flight. But, for my new bag, I'd like to be sure that it will fit the common sizers well enough so that even a cranky GA won't make me gate-check it. (So, something like the Briggs & Riley Baseline Widebody that drops nicely into the United sizer but projects a bit above the metal edge is out.)

My airline priorities are:
1) United & UX 2) Lufthansa/AC 3) American/Delta 4) Copa & other large SA partners

Ideally, I'd like it to fit the overhead bins on some of the smaller United (is it the A320 that's tight?) & UX planes, too. (These are the bins where rollers go in sideways. My Delsey is probably 10" deep, and takes a bit of effort and squeezing to get it in the opening. Something that runs an actual 9" or so would probably be better.)

Overall capacity is really important - I just did a 15-day trip in my (barely compliant) Delsey, including my cowboy boots. I can't really drop down to a 20" size or a spinner with reduced interior space. I don't really care about exterior pockets, etc., as I use my laptop bag for stuff I need to access.

I'm focused on 2-wheel rollers (vs. 4-wheel spinners) for maximum interior capacity, durability, and use on cobblestones, curbs, broken pavement, etc.

Here's what I'm looking at right now:

Lat_56 RW01 - looks like it will fit all sizers, but 7.5" depth seems a bit skimpy for long trips. Cool design.
TravelPro Magna 2 22 - reportedly fits United, but maybe too tall for LH?
TravelPro Crew 10 22" - 11" depth looks too big for United sizer?
Briggs & Riley U122CX - fits United per wiki, but too tall for LH?
Samsonite Aspire Xlite Softside 21.5 Exp - looks like it should work for UA & LH
Claire Chase Classic 21" Pullman Upright - kind of an off-the-wall idea. Dimensions look compliant, but leather construction gives a 9 lb weight. Also have a 22" version.

Any of these known to be non-compliant with the sizers of UA, LH, or other majors?

Does Lufthansa have any extra space in their sizer? They are only 1cm less than United on the height spec, and are looser on the depth and width. Recommendations/thoughts? (Note that my key objective is compliance with the actual sizers. I totally get that you can travel for years with no problems with a slightly non-compliant bag, particularly if you are elite status, look professional, etc.) Thanks!