Simple fix here. Call the guy, Explain that the car isn't your daily driver, and your not in a rush, but you do have other plans for this summer besides waiting on a hood. Ask them to get your car in for pre-fitting and all that because you have engine mods to be done but you don't want to have it apart when they call.

Just explain the situation and I'm sure he will work with you on it. A month is a long time, but he will understand summer plans with the car. After all, this isn't a Factory OEM replacement hood, this is a "My Car is Beast" hood. He will most likely get you in