Andy,
Not questions or comments really

but just a few things to consider. (sorry if it looks like I'm posing more questions, and not offering any answers

)
a) By having a bigger venue would you be looking at displaying more machines ? if so how would this impact RCM in terms of setting up, transport, shut down/clean up afterwards.
b) In making this a two day event, would you expect to increase footfall from people coming one day that couldn't make the other ? or by people attending both days ? or possibly both ?
c) What are the benefits be in terms of increased cash gereation and RCM exposure, against outgoing costs (hire of the hall), loss in revenue if RCM don't supply the food etc.
d) What would the implications be on ticket prices from a one day to a two day event ?
Presumably you are looking for Venue's close to the unit to aid the transportation side of things.
From a personal point of view I would be really struggling to manage two days in may, as it's a week before I go on holiday, and also the Sunday is my Birthday, and I can't see the wife being too happy if I spent the weekend away from home
