@APEX86 OK, thanks, that gives me an idea then. I need to look into it, but there may be an asymmetry in the infill pattern I’m using on the webbing. If I switch that infill from rectilinear to concentric, then I expect that should make it the 100% symmetric.
I retained the beveling of the original makerworld model, which was a brilliant idea by the original author, but I added half circles directly into the print as further prevention against possible warping in the final print, on the theory that they approximate mouse ears. This may or may not be overkill, or even the most desirable geometry, but I don’t mind spending a little extra plastic if it might help. After cooling, if I transfer the printed model onto a piece of float glass (such as the top of the lid of the H2D), it doesn’t appear to teeter totter at all, or bend, no matter where I press on it. At least none that I can feel by hand. By that I mean, I don’t sense any detectable warping in the final print. It seems to be as perfectly flat, as near as I can tell using that method.
Also, I’ll try rotating it 90 degrees and print another, and compare. In theory it would then have no difference, but if it does, then maybe I made a mistake somewhere in my fork of the model.
Well, that’s on me to fix and try again. I’ll do it as time allows. These are good things to print whenever a printer might otherwise sit unused for a stretch of time.
But it won’t be that useful to others, so meanwhile I’ll try printing a calilatern. I presently have v2, but there’s a v3 out, which I’m entitled to as a free upgrade, so I’ll request that and print v3. I did this in the past for v1 on my X1C, and one other person posted their numbers for their X1C, and our numbers were quite similar. If anyone else here would care to print v3 on their H2D, we could compare our H2D numbers. Unfortunately, unless I were to do a full factory reset (which I’d rather not), I can no longer do a before and after vision encoder print of the calilantern. Only an after. However, if someone new, who hasn’t yet run their vision encoder, wanted to print a calilantern v3 (or whatever similar thing you normally do), it would be interesting to know how before and after compare.
By the way, when I import my calibration object from a .stp file, I’m using the maximum triangles the Bambu slicer allows:

That results in the following comment by the slicer:

However, I decline its invitation to simplify the model, as I’m not sure what that does. I’m assuming that “more triangles = more better”, but maybe there’s a point at which more triangles actually becomes worse? Perhaps the motion isn’t as smooth? No idea, but just giving full disclosure in case anyone has an opinion on that.
I do allow “arc fitting” in the slicer, which in general does cut down on print time–sometimes by a lot–but I’ve never investigated whether it introduces inaccuracy or not:

Given the current model and slicer settings, including 8 walls, and concentric top, bottom, and solid infil settings, it takes 1 hour 10 minutes to print, which is fine by me. Using 8 walls means there is no sparse infill, so no assymetry introduced by that. If I were to turn off arc fitting, then on this print it would take 1 hour 11 minutes, which is a minor difference, so I’ll try my next print with it off as a “just in case” pre-caution.
So, given all of that, if you look at how it prints, long uninterrupted lines go away, and so that source of warping (AFAIK, the main source of any warping) is eliminated:
This is the view from the bottom. Thus the advantage of this particular geometry, at least from my POV. I’d be curious whether anyone else agrees or disagrees with that.