We initially allowed investors to manage these properties themselves and ran into a lot of issues that affected the integrity of the neighborhood which then affected the other investors and their assets. 

As others have stated, your fit & finish goals should be guided by whether you plan to:1) Rent: tenants don't always take care of a property, so you want to use lower-grade materials and workmanship.2) Flip: higher quality on workmanship and materials is usually required.Regardless, you always want to "Maintain to the Neighborhood".

What I have seen in the research is to find a property you are interested in and compare to other comps in the same neighborhood.

I love the concept especially given the need in your market for storing things like snow machines, boats, rvs etc, but also for repair or general "fab shops".As long as you are seeing the demand in your specific market for these spaces, and perhaps its worth getting some leases signed up prior to breaking ground but thats a personal preference thing, I think the numbers look promising if the use case is there.

Years ago, a friend of mine took on a similar challenge in an older neighborhood near Chicago..he opened up the top floor to create a master suite that felt less like a converted attic and more like a boutique hotel room.

I was talking to a lawyer friend of mine who was involved in a lawsuit where a guy was letting his friend try out his Tesla in “launch mode” in a residential neighborhood.  

A simple baseline plan might’ve steered him toward properties with more reliable maintenace histories or a stronger neighborhood profile, saving him a lot of sweat.

Or try the reverse - rehab a property to Class A standards in a Class D neighborhood and try to get a Class A or B tenant to rent it.Unfortunately, many newbie real estate investors are jumping into buying affordable Class C rentals - expecting Class A results.

If you want a more accurate estimate for rent, use any platform and zoom into your local neighborhood and see what similar properties are advertised for rent.

In total it took 8 months to complete... a simple cosmetic flip on a 1200sqr ft house in a neighborhood that wasnt asking for much.