You could alternatively go for a project that will be longer or shorter.

Flipping is more money in a shorter time span but over the long term renting will always be more profitable.

I look for the shorter term deals no longer than 24 months.

Having sufficient cash flow from residential units with shorter leases can offset that risk.

I understand that when I'm doing transactions with a buyer or seller that I'm representing, that the Pennsylvania "stock" agreement of sale must be used.That said, like many investors I have a much shorter and simpler two page agreement that I have used up to this point when purchasing properties direct.  

They don't pay as much as sales, but they often have a shorter time frame. 

WOULD IT MAKE SENSE TO CARRY A SHORTER TERM (12 -24 MONTH) SECOND IF BUYER CANNOT COME WITH 20% DOWN, SAY IS ABLE TO COME WITH 10% DOWN, AND BALANCE IS THE 2ND TD.4.

Some of mine will renew after their 12 month lease but for a shorter period of time.  

The shorter payback period and higher rates will make majority of buy and hold deals not make any sense.

Some will fund 100% of the rehab cost and about 80-90% of the price but that will be on shorter term loans ~ 12 months with 8-12% interest.