I’ve got a 1600x1000 bed here, but yours is a monster! You would benefit from 16MP resolution, well, the highest you can get. You’ve got 3.475 million sq mm there, so even if you had “perfect use” of 16MP, that’s only around 0.5mm resolution.
The polka dot sheet seems to be OK now. They had some bugs with high res cameras with the 16:9 aspect ratio, but ok now. I’m within a couple mm.
I do recommend the 16MP fixed-focus Arducam with a “2.8-12” varifocal lens (requires M12 locking ring). The stock lens didn’t calibrate correctly in LB for me. It calibrated, but unwarped poorly with regions of large errors.
What we want to do is get the field of view to match the bed as close as possible. Otherwise, you can easily lose half your pixel count in the margins.
The 16:9 aspect ratio is a very close match to 2500:1390. And then you zoom in the varifocal to just enough to cover the sides and nothing else.