% for Co-Signer incentives?

[Sam McCormack]

I'm 18 years old looking to buy my first small multifamily property to house-hack in the next 6 months. I make decent money my age and am very disciplined with it as well. But part of the problem I am in is that a very significant amount of my monthly income wouldn't be accepted by a lender seeing as it would have to be steady for 2 years. My parents agreed to co-sign for me once I can show them I am making good/consistent money to pay for the property. I want to give them a % of equity in the property to thank them for being my co-signer so they aren't taking on that debt for no reason. But i'm not sure how much to give them. Has anyone does this before and found a percent that is fair to offer to the co-signer? Note: Using FHA 5% down and I am paying for everything my own, they're simply taking the debt

Thank you in advance!