It would be great if in the gesture preferences under long press, there was an entry for “pick layer,” which would be functionally similar to the “long press to pick” option in the move tool. This would let you use long press to pick a layer without having to switch to the move tool first, allowing you to quickly paint in different layers. It would be similar to the other entries for eyedropper and autoshape, a simple numerical value that would set how long it takes to invoke.