I too have Hagerty, a bit expensive until you figure it is insured for $30,00.00. It cost me almost $500 per year, but if it's ever wrecked they send a check for $30,000.00. I would rather have my GT than the check, The key factor for them was I was the original owner. Oh also in Nevada there is no limit on the miles I can drive for the year. My buddy in California also has Hagerty, but he has a limit of 500 miles per year. Find out the mileage and then the cost. If you don't drive it over the mileage limit it is fairly cheap also need to limit the amount you are insuring it for.
We have 9 cars on Hagerty. Total of $2800 per year. Only 1 of them has any mileage restrictions (Lotus Elise, and it is the most expensive to insure as well). Our Opel is less than $200 (I don't remember the exact amount) per year.