The one thing you are not taking into consideration here is the greed factor.
There are going to be times when you are going to have to take some short deals, just to keep some income coming in. 15% of a short deal isn’t going to be anywhere near what it sounds like you are going to pay your second shooter for these next four gigs.
If you give your second shooter BIG BUCKS for these four gigs, it is now mentally set in his mind that is how much money, not percentage, you are going to be paying forever! If you run into a run of three or four short deals and try to get away with a shorter 15%, he’s going to either beech about the low pay, complain that you aren’t getting enough money for the gigs, or going to go looking elsewhere for the amount you used to pay him.
Seeing how you have had to build the company from nothing. Find and recruit the people. Go out and find the customers. Sell the customers. Create and maintain any advertizing or web presence. Purchase any additional gear and peripherals. Have had to do all the rest of getting a business going before the first dollar comes in. PLUS have to go shoot these weddings and edit etc, deliver, listen to any complaints, fix any issues that arise and are at risk for any liability that may arise. When you take all that into account, at 15% HE is making a killing and YOU are losing your shirt!
In the industry that incorporates my day job, the average net profit after all expenses, after everyone is paid a good wage, after all deprecations, after all taxes and everything else that legitimately comes out of the checkbook, the average NET PROFIT for a business operating in this industry is just somewhere between 3% and 5% of gross sales. Under 10% NET PROFIT is customary for almost all businesses in this country.
I suggest to pay his day rate and maybe slide him a few bucks in cash when you are packing up as a thank you, if you feel compelled. IT will make a much better impression and won’t screw things up if the next deals are as big.