offering part ownership to developer

Hello all, I attempted to search for this before posting. My apologies if this is previously mentioned (probably). My biz partner and I have been working with a foreign app developer on a React Native app for about the last 6 months. He is geographically distant but seems reliable and has written all the code. We have considered offering him a percentage of ownership in the project for some further developments and ongoing support (bug fixes, updates, etc). With that being said; would anyone be willing to offer some advice? Is this reasonable? What would be a reasonable % to offer? should this be a % + $/hr? How would we structure such an agreement? Thanks in advance!