I'm planning on using a standard referral contract as sufficient documentation.

That's an expensive repair and one I wouldn't want to deal with while I was living there; especially considering if a leak were to happen or if the owner did not have sufficient funds to replace it. 

FHA won't work in this matter, but with conventional loans, if the house can appraise sufficiently, you are fine.  

*insert disclaimers about it being a law of averages over sufficient time and properties

Now you can learn from his vast experience and insight.

I've seen many related discussions on the boards here - but none that explicitly address what I'm looking for - at least in simple terms.Here's the scenario:Project:  Rehab and flip, own for less than 6 monthsHouse built: 1930Purchase price:  $34KEstimated rehab cost:  $50KARV:  $130KHere's what I'm looking at w/ respect to a quote I'm ready to go with:Vacant/Builders Risk Insurance, 6 month policyCoverage amt:  $130K, ACV (gathering RCV is not available industry-wide for house this old)Co-insurance: 80%Liability:  $500KTheft:  $5KMy question is basically - would this be considered sufficient coverage?  

If we connect next week I can also discuss this area as the vast majority of my rentals are in these areas.

As long as reserves are plenty sufficient!

I took out my phone and pretended I was talking to a potential investment partner and I explained to him the vast portfolio of various real estate investments I owned outright or with partners.

That same plan would be sufficient for your property.