If we use an example of a $1 million gain, and assuming the seller is married and hence qualifies for the $500k exemption, then the effective rate is 1/2, so around 8.5% plus ossibly another 3.8% or 12.3% effective rate exclusive of the subjects decision to live in a high tax state. 

what will be the most cost effective tool to evaluate residential properties? 

Understanding the psychology behind effective communication4.

Pretty clever, make products with a side effect so you can also sell the solution to the side effect. 

Compare the 1st/2nd scenario against a cashout refi on the basis of the effective rate at the end of each year until maturity/expected payoff and the global cashflow. 

Here are some cost-effective strategies:BiggerPockets Marketplace: Since you're already active here, listing your property in the Marketplace can target serious investors looking for turnkey deals.

What legal or financial structures have you found most effective for managing private capital at scale?

,,,,, and I just got off the phone w/ the lawyer who created the deed and he confirmed what you say that the lease remains in effect

Also, how effective is their CRM—does it integrate well with other tools, and does it offer automation for follow-ups?

It's been much easier and more cost effective for me to manage than an actual hot tub.