5 minutes, maybe 10. I had all four done and assembled within an hour. They're 12 pole motors so it's a simple ABCABCABC wind, vs the standard 14 pole motor that requires a dLRK wind to perform well. I did have to rewind them as I started with 8 turns terminated delta and it wasn't quite the kV I wanted, so I switched to 4 turns wye (2/sqrt(3) higher kV)

So i'm pretty uneducated here, I have noticed that retailers sell a motor in a few different kv's, but they all weigh the same. That has always confused me, as I was told that it was more, or less turns to change the kv. When you went up in kv, you did half the turns, did you use thicker wire? Also: do you think that the retailers are lying? Did you weigh yours by any chance (before and after...)?

You use a heavier gauge wire. The intent is to fill the stator as much as possible, so you have to pick a wire gauge that works well for the number of turns you want. Termination also changes kV, so if the two different kV's are separated by a factor of 1.7, then they're actually the same wind, just a different termination. They may weigh different by a minor amount, but ideally they would weigh the same as they have the same amount of copper on the stator

The weight difference would be fractions of grams - more weight could be trimmed off by offering 5mm shorter motor wires that connect to your esc than if you were to add 5 more winds on each stator pole for these tiny motors.