As far as educational material, there are some good courses on underwriting in Udemy.

Any information you are willing to share about past projects from addresses, scope of work, estimates, line item breakdowns, materials costs etc.  

We manage over 85 listings.  

Quote from @Amol Kulkarni: Has anyone used Homeriver Group Property Management in Jax and Citrus Spring.

Single-family management companies are seeing interest from buyers.

I have spreadsheets filled with material lists for every phase of the build that includes pricing for materials as well as labor, and sources that I use for them.

If it is a high end housing product you may have to use a designer because they have access to some material/finish suppliers that are otherwise unavailable but that tends to only be for the highest end housing deliveries.

Try interviewing at least three managers.1.

And sometimes, we are not materially improving what you could have done  yourself. 

I'm a property manager, and I also buy/sell property.