I'm now courting builders for plans and estimates, narrowing down to few I've shortlisted. 

The MAO formula (70% of ARV Minus Repairs Minus Wholesale_Fee) only makes sense for fix-and-flip deals.For rental deals, you'll need to calculate the metrics that matter to a landlord, starting with Cash Flow and Cash-on-Cash-return.To do this you'll need to estimate Income and Operating Expenses to get Net Operating Income (NOI).

My estimates are that I would NET $100k per property after taxes and commissions.My income will basically stay the same. 

Second lowest property taxes in the nation behind Hawaii.Montgomery county tax estimate formula is: appraised value x 20% (without homestead) x .0365

Scott The Book on Flipping Houses,The Book on Estimating ReHab Costshttp://www.biggerpockets.com/flippingbookLocate and attend 3 different local REIA club meetings great place to meet people gather resources and info.

Unless you have a specific property under contract, there really isn't anything other than some rough numbers and estimates. 

Research analysts at Jeffries recently estimated that a $2.7 trillion refinance boom could start soon.Current odds on Fed rate cuts at upcoming FOMC meetings below.

What you don’t know or check, can come back and bite you in your estimating & repair.  

These smaller deals are much easier to estimate numbers and look at as there are not as many moving parts.  

In a long-term context, May vacancy rate is 0.5 percentage points lower than the 4.8% average recorded since the beginning of Q2 2014.Market OutlookREIS's new construction analysts report that 6.9 million square feet of new multi-tenant warehouse/distribution inventory will be introduced to the metro by the end of the year, and net total absorption will be positive 9.1 million square feet.