I'm trying out Astropad Studio on an iPad Pro with Pencil. Bit miffed about subscription model and basically making my standard version redundant, but I have a tip for people using Photoshop.
As default the shortcut keys in Astropad include Brush + and -, undo, redo, zoom in and out. All perfectly reasonable, but you can do all this a lot faster with a few minor changes.
You probably already know you can erase by holding down one finger and 'drawing', so the erase option doesn't need to be there. You can also zoom in and out with gestures.
But the really cool thing you can also do is this:
Delete the Brush + and - buttons.
Then add a new shortcut (I've called it resize) and assign it to both the Ctrl and Alt keys.
Now when you hold down that shortcut, you can resize your brush by dragging the pen left and right and make it harder or softer by dragging up and down.