What are current loan terms today versus 2 months from now versus in 2 yrs?  

Just want to mention that sometimes it works out better to raze an existing property down to like 2 studs and rebuild around it so that it still is classified as a remodel versus a complete new build. 

The 15% tax hit is a one time expense, versus 4.3% is annual interest.

If I was to build a location with 200 units, versus the 4,000 that already exist at 90% full. 

Connecting with local GC groups in your area will help you connect with subcontractors, find out tips and tricks of the trade in your local area (since all areas and their real estate differ slightly).Also, have you considered the motivation behind building a brand-new duplex versus finding one on the market?

Your primary strategy should be to have the Contractor and all Subcontractors add you to their insurance policy as Additional Insured. 

In The Millionaire Real Estate Investor, it profiles a couple who used this strategy.

What financing strategy would be most effective?

National debt versus GDP3.  

Quote from @Diyan Yap: Welcome Mark, we are both in Texas.What strategies do you know and have you found any deal yet?