My suggestion would be to make it clear first and foremost how much speed buying the next level of an aspect will give you. This will make it easier to know which upgrade is the best value for money. Knowing the total base speed is not very helpful as as far as I've seen only the total speed after multipliers matters at all. In other worse, replace the "total base speed" area in the tooltip with something like "next purchase speed increase: [base speed x total multiplier]". Yes, I know I can calculate this myself, but I'm lazy! Otherwise, this is a fun game so far!!

A percentage increase appears on screen every time you upgrade anything. Also, in my opinion, it's a quick clicker game which doesn't require overthinking. It's no great loss if you spend on the wrong item as you get the currency back quickly, especially once you're using meditation points.

Tooltips will continue to be worked on as more stuff is added. I'll take a look about this request as well, thank you for the feedback.