I too am having issues trying to edit Grade. It's the only issue I see with program. But, using Turtles program, I was able to export my save and edit it with HxD. I'm somewhat new to hex editing, but still know some of the basics. I was able to find/change my Gald and Arte usages, but not grade. I can't even find the correct value by searching. I had 1074 grade with one file, which should be"32 04" in HxD. Another file with 1064, which should be "28 04". But no search results. Nothing around the a7708 address area. At 000A7708, I have 48 19 85 44 (1064 grade file).
Am I mistaken? I'd like to contribute in anyway i can.