When discussing any split with the bar - you must (as Landarc pointed out) make it a split of the profits NOT sales. Unless the bar is kicking in a % for at least the supplies, then your % will be covering material costs PLUS your time PLUS a VERY marginal profit (maybe). Meanwhile, the bar gets pure profit for their %. Better might be to make a decision on how much you think you'll make in profit - let's say you're clearing $3 per item x 200 people = $600 & offer the bar $100 as "rent" for the day.
Cha Cha Hut BBQ : 43311 Route 28 (corner of Route 28 & County Road 38: Arkville, NY : [URL="http://chachahut.com"]chachahut.com[/URL]
Backwoods Pro Jr.
busted Backwoods Fatboy
Weber 22.5 Kettle
some stainless wood fired thing