The default shortcuts for photoshop kind of suck, but damn this looks terrible. If you have to hunt around and move your hand a large distance to press the key for the tool you want, you might as well just use the mouse.
Ideally you want something that you *don't have to look at* to use, and can access everything you need with one hand while the other is on the mouse. Something like one of those gamer keypads would be alright. But better would be e.g. half an Ergodox. [Well, Ergodox has a ****ty thumb layout, but the overall idea is there.] Multiple thumb key modifiers + the keys in the main letter area to activate all of the common Photoshop tools sounds great.
(Unfortunately, I don’t know any keyboard firmware which easily allows several dozen key macros, which you might need for this kind of thing.)