I think it's the part where you say you may need help in the future that may be turning the sellers off.
Buying from a retailer who offers support is one thing. Buying from a collector is another. There will be plenty of opportunities for community, and there are lots of good people here who will help you through tech issues, but a seller doesn't want to get a bunch of follow up calls/questions after the sale, so I wouldn't even mention this is your first pin in your communication.
Also, especially if a pin is priced well, you can't be too picky about when you can come pick up the machine. Sellers will generally sell to whoever shows up with cash first. A seller won't want to hold the game for you to look at if they have offers.