I know the basics, you can see if he wants to battle every day "after lunch" and he gives you a HP up. I'm curious if the hard and fast rules are known.
Like what times exactly it works in between, if you have to call him, or what. Been trying to experiment myself but things seem to keep messing up, things possibly including me. Sometimes it seems he won't battle even though he said he would the day before, or that he finished lunch and I can't battle, even though I am almost positive I fought him at that time before. It was like 6:30 PM when that happened. Assumed the time was 10-8 for being in the afternoon so then I wasn't sure.
Any definites that people know would be much appreciated while I try and bumble my way through it now.