One option is to make equity based on achievements. So both of you can create a list things that need to be done by a specific time and then split it between yo

One option is to make equity based on achievements. So both of you can create a list things that need to be done by a specific time and then split it between you two. This should make it very clear to the non full time partner that he isnt getting much done. If he is able to achieve the milestones then its probably a good thing to have him on board even if he's part time. A startup is all about getting shit done. Dont worry about hte time he;s spending at the job.