Out of the 50 addresses zero will probably be interested in selling so it's a numbers game before you find the one. 

What is the most cost-efficient way of updating the deed records?

Given how the housing authority does their rent price determination on individual units, and government ran programs are never beacons of efficient processes, it can go either way.Note, the examples I speak of only relate to C-Class and below areas.

I just haven't been able to hook up with them yet.I know I am not allowed to post my email address here. 

See the chart from Fair Isaac Company (FICO) below: FICO Score Pct of Population Default Probability 800 or more 13.00% 1.00% 750-799 27.00% 1.00% 700-749 18.00% 4.40% 650-699 15.00% 8.90% 600-649 12.00% 15.80% 550-599 8.00% 22.50% 500-549 5.00% 28.40% Less than 499 2.00% 41.00% Source: Fair Isaac CompanyAccording to this chart, investors should use corresponding vacancy+tenant-nonperformance factors of approximately 5% for Class A rentals, 10% for Class B and 20% for Class C.To address Class C payment challenges, many industry "experts" are now selling programs to newbie investors about how Section 8 tenants are the cure.

.#3:  Short cuts are not efficient. 

Consider all the things that could go wrong and see if the lease addresses them: unauthorized pets or tenants, early termination, security deposit, lease violations, late rent, eviction, lawn maintenance, parking, etc.5.

On paper some of these buildings had amazing metrics, excellent cash on cash returns, cap rates, etc, but when I looked at the buildings I found the neighborhoods were rough, there was poor management in place, there was lots of deferred maintenance to address.

Thank you  Using a LOC on your primary residence can work well for flips if the terms are favorable and you’re confident in managing projects efficiently.

Not gonna give address's here because not trying to market them here, just pointing out reality that when your a 24-7 professional "hunter", you tend to know where the deer are all but on demand.