Although I ran across a post that said on your first deals, give yourself a 1.5x multiplier on time and costs. 

Divide the amount being carried ($70K), by the amount required (80% of $170K), multiplied by the amount of loss ($65).

I'm going to use additional calculations like cap rate and gross rent multiplier to compare similar homes to find a great deal.

Dose the general rule of thumb "declared income multiplied by 5 equal maximum loan amount" Cash would than make up the difference. 

They will multiply the gross rents by a multiplier to estimate value.

Right.. but multiply your 7 units by a factor of  about 5 to get the poster's scale...

Normally, I just multiply my rental income by 12, minus yearly expenses and divide by the total price of the house.

What are the comps gross rent multiplier? 

I’ve commonly seen equity multipliers being used in value add deals, either mentioned by investors desires or even included in offering memorandums. 

In such cases, the net income of each activity with positive net income for the year is multiplied by a fraction: the numerator is the combined net income for all significant participation activities, and the denominator is the combined net income for the activities with positive net income.Eg: Betty is a full-time teacher, but she also owns stock in two S corporations (Acorp and Beecorp) that pass through income to her.