I have flipped new homes and townhomes but phased out raising a family and now am focused on utilizing my skills which are building, selling, expanding a circle of influence to focus my effort on the above.

If you research recent sales you can always provide the appraiser a list of those sales.One of the best ways to insure a higher value is to update the property using materials and fixtures that are popular and common in the area.

What is he charging for the materials?

HOW TO SHARE UTILITIES 101You have a property with two or more units and the utility meters are shared.

You can break it out by general RE activities and material participation.

There's some excellent relevant & recent material from very high quality individuals on this forum.

Right now the only utility at the garage is power so basically I am starting with a frame and a roof. 

These typically include services like renters insurance, HVAC filter delivery, pest control, and sometimes utility management.

To address this I took detailed pictures from beginning to end of my most recent flip, documenting that we did a thorough job using quality materials.   

I'm currently reading David Greene's "BRRRR" book and I will be utilizing my VA Loan as a first home purchase (duplex) for my first home utilizing the VA Loan.