I put mine on the household, BUT, they insist on a professional valuation. Fortunately, I know a registered musical instrument valuer who's a folkie.
He's not likely to be of use to you as he's here in NZ, but you could ask luthiers and instrument repairers, which is what he is.

Never had to claim for instruments, fortunately. I'm very happy with the company, though. They paid up promptly and fairly on the claims I have made.