If there are 2-4 partners delegate out responsibilities, years ago I was in a 4 way. 1 took care of the schedule he was also a CFII and did BFRs recurancy ect. 1was a CPA he handled the books that included a monthly detailed statement. 1(me) took care of maintenance scheduled annuals oil changes and such it usually required a 1/2 to1 hr test flight

. 1 made sure the plane stayed clean. We lumped fixed costs, hangar rent, insurance, plane payments ect divided it by 4 and those were fixed monthly payments.
We flew hourly paid for our own fuel and charged $40 per hour went into a maintenance reserve, that paid for annual (owner assisted) tires batteries ect the rest was for engine, prop and other unforeseen stuff. It was a real comfortable partnership no conflicts ever.