I am in a 3 person partnership in a certified airplane. The plane is owned by a Delaware LLC and we have equal shares. Our agreement closely (blindly) follows the AOPA document. Get yourself a lawyer to write yours. I wish we had.
Partnerships are like dysfunctional families. There is always a brat amongst the partners, too. Still, it is the only way I could own & maintain an expensive certified A/C, so you take the bad with the good. And there is some good.
Feel free to send a PM with questions.
Best of luck.
John