Thanks for using a Grunt Fund! You are off to the right start with your business. The model should feel right, unless something is askew. My gut tells me that you are contemplating taking the commission on top of a fair market salary that is similar to your partner's. So, when you do your job well you get gravy, when he does his job well he does not.
At the core of the Slicing Pie model is fairness and it uses fair market rates to establish theoretical value (I now call this value "slices"). Traditionally, dedicated sales people get a base salary plus commission. Relative to other people at the same level in the organization, a salesperson usually takes a lower base salary. Target compensation would be similar to other managers at the same level. However, if the salesperson knocks it out of the ballpark there is the possibility for upside.
If you two consider yourself "equals" in terms of your level in the organization, your skill set, experience, education, etc, you should both have similar compensation. Let's say you both deserve $100,000. Your developer probably expects some kind of parity.
The developer would have a GHRR (Grunt Hourly Resource Rate) of $100/hr (($100,000 x 2)/2,000).
Your salary, however, would be a mix of salary and commission with a target of $100,000. So, if the going commission rate in your industry was 10% and your target revenue is $1,000,000 this would imply a base salary of $0 for a commission-only position. If the commission rate is 5% this would imply a base of $50,000 of a GHRR of $50.
CEOs, Presidents and other non-sales possessions generally don't take a commission. Only people who are dedicated 100% to sales do. In return for the luxury of focus and the ability to earn a lot of money, they take a lower base plus commission. Commissioned salespeople are usually not roped into other managerial responsibilities.
So, determine how much of your job responsibility is dedicated to sales. Use that to determine your fair compensation. For instance, if 50% of your time is sales then earmark 50% of your compensation to be commission. Set your sales goals to create a target compensation similar to your partner.
Think of it this way. If 100% of your job is to generate sales and you generate $0 in sales you don't deserve much. If 50% of your job is to generate sales and you generate $0 in sales you deserve half of your compensation- the non sales half.
If your job is to generate sales and your revenue target is $1,000,000 and you sell $1,000,000 you did your job and you deserve as much compensation as other managers at your level (namely, your partner).
If you hit $2,000,000 in sales your partner should be happy to compensate you at twice what he earned because you are over delivering in a very real way.
If you both aren't comfortable with this arrangement something else is wrong. Feel free to contact me through SlicingPie.com and I'll help you get to the bottom of it.