You may want to institute a referral fee, based on a % of the job payout, and an information fee based on the job payout, but with a time limit of so many hours, also based on the job payout. I would believe that % should be pretty low, say 10% to 20% max, each. Keep in mind that you are not actually doing the work, he is.

For instance the job at hand is a $2,000 job. your referral fee would be 10% of the $2,000 or $200. Then if he needed advice on that job, the information fee would also be 10% of that $2,000 job, or $200, but you time limit for the information would be limited to 2-3 hours. So if you both referred the job to him, and provided information concerning that $2,000 job, he would pay to $400 with a time limit of 2-3 hours on the information consolation.

You get something for sending him work, and you get something for the time you share your experience, and he knows what your referrals and experience will cost him and then he can determine how much, or how little of your help he desires from you, and when he might want that help. The time may come that he won't accept jobs you send him, and/or he won't be asking for your experience as much. If and when that time comes, respect his wishes.

Selling specialty tools and materials should be based accordingly. Get back what you paid and maybe a small profit, but well under what it would cost to buy the same stuff on the current market.