The higher valuations make it difficult to cover the mortgage and reserves with the lower rents.B is a good area, but not as valued as A.C and D areas will have a higher percentage of people that rent vs. the A areas.

In most instances they charge the first months rent as a finders fee plus a percentage of the take per month.  

She will receive the initial "buy" amount that we agreed on, a portion of which is going to be paid up-front in order to bring her mortgage current and give her enough to move out to Ohio, and then a percentage of the final sale amount.The reason this flip works is because we are avoiding going through two purchases and also avoiding financing fees from a HML on the purchase of the house, since the owner will still own the house during renovations.Since she doesn't own the house outright, this isn't really "seller financing," but maybe more like a joint venture?

All of your reserve percentages are too low.

The properties I have been analyzing seem to have a low percentage based on the asking price.

The interest rates are higher than conventional loans and a small percentage of the loan called "points" is paid on closing.

Is there a rule of thumb as far as percentages?

I am interested to hear what percentage of deal you typically like to buy as an investor for a flip property.

I was thinking 12% interest, and a percentage in the ownership of the deal? 

You can interview other agents.However, in reality, there are a good percentage of agents that either 1) Will not know how to analyze investment 2) As you said, are not savy with off market 3) Are not familiar with real estate investing in general.Not to say they are not great agents in finding a home for the general population.