I went with Grundy's at $365 a year for my GN with said value set at $24,000. Real nice people. Unlimited mileage, no deductibles, and I choose who does the work in the event of damages. Hagerty wanted $567 a year, with a 2,500 mileage cap and a $500 deductible (Hagerty's does have roadside assistance included but I can get AAA and still be ahead with Grundys). American Car Collector (my present insurer, USAA recommended them) wanted about the same amount as money as Hagerty's.
With all them, it has to be made clear that this is a pleasure vehicle and you must have a daily driver for each licensed member of the household. No stopping for gorceries or driving it to work, but taking it out to eat is okay. Your not supposed to race the vehicle, but modding it is okay (with Grundy's at least).