If you really want to know what it's worth, put it on eBay with a big reserve. I think you've probably missed the peak, and you probably can't get what you were offered before anymore. It seems like there's a lot of cars on the market, lots of high roller collectors selling off their stuff. When you see real Hemi Cuda convertibles on eBay, there's something different going on. I'd love to have an E-body convertible, but I'm going to wait because I think the prices aren't anywhere near the bottom yet, and I want one that's already done. I bet there's a lot of guys who owe their restoration shop more than their car's worth right now, so selling a project is probably going to be harder than it was a couple of years ago.
Good luck with it, whatever you decide to do. It's a cool car, and I hope you finish it, and get to enjoy it.