For reference, my hand's 19x9.5cm.
I've been using my Stellar Black Mini on and off for a little over a week now and have been really enjoying it. It's sized and shaped just about perfectly for my fingertip grip. That along with the fact that it's the lightest mouse I've ever used has made it a new favorite. It's too small for me to claw comfortably, but I can see it possibly working for smaller hands. It's also quite narrow, so wider hands (maybe 10.5cm+) might have a hard time even fingertipping it.
Build-wise this thing is solid. I haven't experienced any creaking, rattles, etc. The main clicks are super crisp and are right in my personal sweetspot for activation force. One thing to note: the table abovethat shows the different specs for the Mini, Max, and 8K lists the switches as Huano Transparent Blue Shell Pink Dots, but mine are definitely the TTC Nihil Transparent Black Dot. I'm guessing they changed them between batches (and I think WLMouse's page now lists the TTCs).
I love the look of the glossy coating on my Stellar Black, but I could see it possibly being a problem for those with sweaty hands. Mine tend to be pretty dry, so I'm not sure if it gets slippery with a little moisture.
Overall, I'm really happy with the Mini and expect it'll be in the rotation for long time.