This deposit is clearly defined as a holding deposit, not a security deposit, and my Holding Agreement spells out what happens from that point forward so there's no confusion. 1.

This note spells out the terms of the money that you are borrowing.

If I were to enter into a deal such as this I would draft a contract that spelled out the payment schedule that both parties would sign. 

It is good practice to spell this out in advance in the purchase and sale agreement for the partial.

please disregard the spelling in the title.  

.@ Lori GreeneYes I meant to say "interest", not "internet", stupid auto-correct or just poor spelling.

The reason why the CAPEX percentage is different with those that use it is because their guessing (sometimes spelled "hoping") that the money will be there when they need it...in the amount that they need.3 - Use 10% for PM. 

You just mentioned an LLC operating agreement(OA), this document should have all the terms spelled out within.

Create an actual legal partnership (LLC, talk to a lawyer for specifics), spelling out who will do what, and most importantly, how the partnership will end.

Set up an LLC and have an attorney draw up the partnership documents that spell out everything BEFORE you start any work or start offering for deals.