Here's some numbers:-Worth 230k-240k in today's market (I live in Clovis, CA)-I still owe 189k (40-50k in equity)-It was built in 2006, so its relatively new. i.e.

I own my home with 1 mortgage and have about $65,000 in equity.

As a percentage, we are also very similar in equity position -this being a factor of how and when we purchased.  

Leaves a total of $60 a month in cashflow and aprox $290 in equity pay down to be shared.

But, it sounds like you'd prefer more of an equity partnership instead.While it's natural to want a simple answer when it comes to how to divide equity/profits within a partnership, rarely is the answer simple...You need to sit down with your partner, make a VERY detailed list of everything that each party is bringing to the table, and then assign either an hourly, fixed or equity value to each thing.For example, the list may look like:YOU:- Finding the deal- Renovation costs ($50,000)- Creating the scope of work- 50 hours of contractor work you'll do yourself- Finding and interviewing contractors- Managing contractors- Making design decisions and handling materials- Accounting for the project- Staging the house- Finding the real estate agent to list/sell the house and managing the sales processYOUR PARTNER:- House costs ($50,000)Now, instead of assigning an equity split for the whole project, it seems more reasonable to assign some hourly costs for some things (the contractor work you'll do yourself, for example), and it seems reasonable to assign a fixed cost for some things (the staging work, for example) and then assign equity for the rest.So, for example, you may negotiate and come to the following agreement:-  You'll get $25/hour for any contractor work you do-  You'll get $1500 for finding the deal-  You'll get $2000 to stage the house-  You'll value the monetary contributions as 70% of the total equity -- if you're each putting in equal amounts of cash, you'll each get 35% of the equity for your contribution-  You'll value the rest of the management work as 30% of the total equity -- if you're to do all the management work, you'll get 30% equity for your contributionIn the end, that would give you $25/hour for the contractor work you do, $1500 for finding the deal, $2000 for staging work and 65% equity.  

I in turn negotiated 30k off the asking price and gained 10k in equity because of the problems the house had. 

You say you have $250K in equity but also say you're 99% financed at $1.3M.  

One is completely paid off and the other two you have 50k each in equity (so you have a 150k mortgage on each of those two houses.)Now you want to acquire a fourth property that costs 200k but you do not have 50k to put down, so you cannot get a conventional loan (which requires 25% down on an investment property.)Is there some way to use your equity in one or more of the houses as collateral to obtain a mortgage for the new (4th) house?

A decent cash flow play with some built in equity.

Where I do need to be careful is things like utilities as those will mess up the 50% rule pretty quick and create an apples to oranges comparison.IMO, I don't know why anyone wouldn't take 30 year financing... the opportunity cost of tying up cash in equity versus reinvesting it right now is HUGE.