Need Advice: How to pay "partner" after initial first flip

[Bethany Kerr]

My first flip closed in March and was a huge success.  I self funded the project 100%, but, agreed to pay a friend 35% on my first flip for his knowledge from pay flipping experiences with a family member.  He helped with managing contractors, making runs to the house when I wasn't available, painting, etc.  I'm currently under contract on a new property that doesn't need nearly as much work as the first.  I don't feel that I need him for more than odds and ends tasks that I'm more than willing to pay for, but, do not believe 35% is anywhere in the ballpark of what would be appropriate to pay.  I found the house, comped the house, have already had contractors quote the few jobs necessary and will be employing my 16 year old son to do things like pressure washing and painting with me.  I need to have a conversation with him in the next day or two because I can see he's assuming the same pay for this project.  I feel like I need to move towards and hourly pay or project based pay at this point.  Any input is greatly appreciated.