I can't even count how many posts exactly like this I have seen on BP. Typical story, the contractor is the"partner" but will only be doing contractor work, yet the other partner will give him half. What a gig!
Your contractor is adding almost no value here, above and beyond the value of a contractor. All contractors get materials at discounted prices. If your loan is a typical loan, each of you are fully responsible for the loan repayment. (If he was was splitting the loan, and thereby splitting your risk and need for capital that would be different.)
I see 2 ways for your partner to add value and therefore earn more than contractor wages. #1 provide the labor and materials to the LLC for free, and get paid at closing rather than in draws as work is completed. That adds a ton of value because it's that much less you have to borrow @ 20% interest. Don't kid yourself HML is 20% when you add up all the fees, costs, appraisals,draws, points and interest.
And #2 if he can be a true partner and not someone who needs to be managed, but rather do some of the managing and "boots on the ground" type stuff, that should be valuable to you.
I have run a lot of numbers on flips, and depending on your price point and scope of work, generally the guy wearing the "rehabber hat" earns 1/3 of the profits, the "investor hat" earns 1/3 and the "Realtor hat" earns 1/3. So my experience tells me you'd be earning 66% and taking 50%.
$30k pp & $140k arv = rehabber makes more $300k pp & $500k arv Realtor/Investor make waayy more