There are a lot of things to consider.....
1...... People are asking about other(winter?) months. That might be tough for some people. There are always unpredictable winter storms that could have airport delays or cancellations. Also... For the dealers that drive across the country... Driving in winter (snow)could take much longer and be dangerous. We are all getting a little older. (I fly.. Doesn't matter to me 😁)

2......Changing locations...you might get more people looking in our convention, but you might also get more "unwanted" or "undesirable" people off the streets. More isn't necessarily better. We need good "quality" people. Could hand out cards/flyers on the strip??(like the naked lady flyers 😜)
3.......Show admission.......you could have a special token (or chip) for visitors. They pay $5 to get in and they get a $5 token to spend at a dealer. If they don't buy anything after their visit, they can sell it back at the door for the same $5. It might get them to come in. Spend a few bucks. Or at least have a look without having to be out the $5. I would be willing to bet that most of the "visitor" chips wouldn't be redeemed back at the door. The dealers would then turn the chips back in to get the money back. Maybe do a deal where the dealer only gets $4 back and the Club gets to keep a $1. Most of the chips would probably end up in collectors hands or on eBay a week after the convention. Would the Club get any profits from unreturned chips? It might be small, but anything positive would help.

Just a few thoughts....