too bad there is not easy solution, but nice to hear you are already working on it.
However let's say I'd be fine with just editing the code to change this one assignment in particular from alt+leftclick to ctrl or shift + leftclick. What I would need to do essentially is replace event.alt with event.ctrl / event.shift in sprytile_modal.py, right? So far I thought the lines 818-820 invoke the picker but obviously that is not whole story.
Can you give me a hint on where / what I need to edit?