Also, wanted a small auxiliary monitor under the main one for a long time. This shelf finally let me do that.
I've been looking for a Bluetooth-enabled analog watch with a diver-style rotating bezel for quite a while. I was excited about SKXmod Tuna, until I realized it's so ridiculously big, I could never pull it off, and I do wear some pretty big watches. Trent Tech Tickers (u/Ptr3nt13) achieved this mod with only 43 mm case diameter, 11 mm thickness, and 49.5 mm lug to lug. Yes, it's still not at all a small watch, but it's very wearable.
The mod is designed for GA-2100, but works with GA-B001 as well. Doesn't come with a bracelet, but looks great on a lot of straps (and it's a 22 mm lug size, so there's no shortage of options), and I will find a bracelet that fits eventually (pictured is Edifice ECB-30 bracelet).
Casio Wave Ceptor WVA-320J. The only (other than Oceanus Cachalot) auto-adjusting diver-style watch that I know of, at least from Casio. If you know any other, please let me know.