There is no magic math. You are asking to purchase between $500k to $2.0 million worth of real estate with $60k. I hope that was a little shocking after you read it too.
I think it is awesome you have a high unit target but it may not be practical at the dollar figures you are talking about. It is going to be based on the debt provider relationship you can get. A bank, hard money lender or even another private investor willing to be more of a debt provider can offer potential solutions.
The buy and hold strategy is good but it is not clear you have thought about how to recapitalize your venture. Once you put your money into the asset via down payment, closing costs, repairs or whatever how will you cash it back out to buy your next asset?
An answer of refinance there presupposes you are purchasing properties with equity in them and you have lenders who will allow you to cash out that equity. Assume that no lender is going to let you remove all of your skin in the game, lets assume 90% would be the max loan. Remember as well, that different lenders will have different terms regarding ownership time seasoning before they will allow you to realize untapped equity as this is the same as allowing you to remove your skin from the game.
A local bank might be willing to setup a relationship with you to workout rehab loans where they finance the purchase and repair costs. That same relationship may also be inclined to work with you and allow you to cross collateralize some of your properties using the property equity to allocate new debt. Most of the time you need a little bit of a history to garner this type of relationship with a bank but perhaps your general contractor has a bank relationship he can leverage off of. (this would bee the "blanket" loan you refereed to)
Obviously a solution to the re-capital is just raise new money. Another thought might be to look for properties that you can buy and sell.
Again you have some dollars to go make deals, it only takes one to start. It may make sense to sit down with your partners/investors and think through the plan. Start small and manageable, you don't know what you don't know yet. It takes money to own real property so you need to setup a budget for each of your projects whether it is buy/hold or buy/sell. Include all costs including your debt relationship and a contingency for things you didn't plan for.
As I opened with there is no magic math that will whisk you along the path of success. Assuming you will have around a 10% equity stake in each property for your $2.0 Million you still need to make or raise another $140k plus, chase your dreams but keep them rooted in reality.
