DSCR loans are based off of down payment, credit score and either actual or market rents so it helps to supercharge an investor's real estate goals and net worth.

We listed strategically and were under contract in 2 weeks in the slowest part of the year (December) whereas all the other similar homes in the neighborhood have been sitting for months and still sitting on the market. 

I'm in the Tampa market.  

It's important to know what market rents are for what you are analyzing, many properties are super under rented and you have to get them to market rates. 

Quote from @Jacob Sherman: What type of loan products are you in the market for ?  

Or do I look into a market like Las Cruces, NM, or Lubbock, TX, as an example of bigger markets I have looked at and am somewhat familiar with?

You may also be able to "make your market" if you can hit a critical mass.

It is still a seller's market in many geographic locations, so you can ask potential buyers for an extended closing period and/or with options to extend the closing period. 

Quote from @Kevin Hintz: I can totally relate to the tight market and how hard it is to find deals.

The guru your son is learning this technique from is likely not telling your son that the deal will almost certainly encourage your son to get an "off-market" deal from a "wholesaler" who is unlikely to properly disclose the details of the property or encourage an inspection.