Many properties are unrented, even at heavily discounted rates.  

What I'm hung up on is how to make a deal work so that it produces a satisfactory rate of return for the money partner.

I guess the choice is really up to youThese prices all depend on the area.

Depends.

But given the high-interest rate and expanded cap rate environment, I feel like there may be some good opportunities for vulture GPs/Operators.

Storage occupancy rates during past recessions has remained relatively stableFor example, during a recession, when folks downsize from a 3 bed/1 bath to a 2 bed/1 bath, those people, historically, keep their belongings and put them in storage.Also, during inflationary times, self-storage operators can better manage rates because most leases are month-to-month.

Depending on the project's size, construction might take around a year.

When I sell a property with owner financing I want an interest rate of 2-6 points higher than the Lowest commercial rates.  

And depending on how conservative your compliance attorney is, you are generally allowed to market a company under 506(b) rules.

How beneficial the study is to your specific situation is dependent on a lot of factors.