If you do outsource first, I would not strictly focus on the management fee percentage (i.e 7% vs 5%) ... some of the most expensive property managers I've ever had have charged the lowest fees; 5% does not mean a whole lot if they pick your pockets with marked up repair invoices, select bad tenants that don't pay rent & trash the place, and ignore the repair requests of good tenants causing small problems to get large.

Should I have just the down payment ready, or the down payment+closing costs, or a certain percentage of the entire loan?

What I do is make an offer I feel comfortable with and offer the seller a percentage of the overage. 

I would highly suggest you use a company that works on a percentage of the total income as opposed to a flat fee.

My issue is understanding all that is involved in actual closing costs and are these fees a reason to shop around for lower closing costs or are closing costs a certain percentage across the board. 

Is there an average percentage or is it a case by case?

Thank you all for your answers it helped me to start getting the idea.I'm looking to learn more about hard money, especially the reasons people are using HML, the risk for the lender, default percentage, etc.If any lender is willing to have a chat with me please let me know.

Even when I advertises 15%, or a particular amount or percentage like this, it does NOT mean and/or it is not a must I add a dime towards tenant-buyers future down payment money, this is also part of making your phone to ring off the hook and also know and have a much tenant-buyers in your d-base as possible.I hope you get my message, we have all used different phony ways to get thousands of cash buyers within 3 hours in our different cities, this is not an exception.

., can you summarize your EXPECTED expenses ie. if not totaling 50%, then what is your realistic percentages for cap ex, vacancy, insurance, taxes and maintenance?

My recommendations:1) Take a trip to Milwaukee to see it for yourself2) Be prepared to lose some income when you hire a management company, in addition to the percentage they take.