So this is where I need to refresh my memory. The Zepp Watch Designer gives you a .zab file, which is a zip file containing the dial.bin (which is 1.7mb in my case), a manifest.json and another zip, which contains the source.bin (which is 282.8kb for me) The AmzfitWatchfaces sites, irrc takes the source.bin files, I downloaded mine from when I uploaded it and the bin is 214.8kb. -- mind you this bit is on me, as this applied to what I made, not one that is downloaded.

Because I tried Gadgetbridge and both "worked" fine but mine resets back to the default watchface, so mine could be corrupted.

However, prior to this, I got the compatibility error with all tested files. -- After Re-pairing in AmazFish however, the downloaded watchface seems to be sending now.