Ultimately, like anything the value of these guitars is either what someone else will pay for them or what they are worth to you.
If you're simply looking to move them I'd suggest taking the book prices, double them and stick them on Ebay/Craigslist with that as a BIN or best offer price and take decent offer. If nothing is forthcoming then drop by 30% and try again.
Insurance valuation - then book price +100%
If based on what they are worth to you then how long is a piece of string. My old Tanglewood TW400N is one of the earliest out of the factory in Korea and doesn't look like it had a piece of machinery near it (pencil marks all over the insides, braces obviously cut and finished by hand, file marks and the odd finger print!) Doesn't look like it had a luthier anywhere near it either (see previous sentence) and is probably worth £25.00 ($40.00) on a good day. However, knowing its history, the abuse it has suffered in terms of huge variations in terms of temperature (sub zero to 120+F) and humidity whilst living without any sort of case in an uninsulated loft space for several years, and yet the neck is still straight as a die, the top is flat and it is still structurally 98% (a brace needs a touch of glue) plus it has been with me through thick and thin for over 25 years we would be talking 5 figures before you'd get close to persuading me to part with it.