The strap tightens, and fastening to the next hole makes it too loose, what should I do?
You need to wet the strap, fasten it to the position that just presses it. And to put on something similar in size to your brush, but larger by a few millimeters (about 5-8). For example, a round bottle of shampoo or deodorant, a tube from a towel, etc.
If all the diameters are smaller, put on the strap and take between 1-2 pencils between it and the bottle.
Then just leave to dry at room temperature. After 4-7 hours, the strap will dry completely, and the skin will "remember" the stretch. Wearing a hand strap, you will feel that now he sits comfortably.