I've been cooking hotdogs for an annual event for 4-5 years and it'll be anywhere from 1400-2000 hotdogs, and one thing I've learned is that I never get the amount of condiments right. I take notes, refer to them, etc. and alway seem to have at least a couple gallons of mustard and ketchup left over (probably 'cause I'm always scared of running out) and I'll go from having too much relish to not enough. So in other words, I don't know. :doh:
You have plenty of ketchup and mustard, that's for sure, 'cause I use somewhere around those amounts for the events I do. You could probably get by with half that...but just to be safe...:becky:
We have a store out here called Smart and Final where you can get gallons of mustard and ketchup with pumps on them, which are great. You can also get gallons plus the pumps you can add on, but they're a pain when it comes time to change 'em out and you're in the middle of a bunch of other things you need to do. Obviously it's much easier just to switch out the whole deal. Not sure if you have an equivalent store out your way, but something like that should be available in your area, methinks.
And, like the other condiments, I have no clue about the onions - not everybody will use them, so it's a tough call.
Also - not sure how you're cooking them, but if you're using your smoker or grill,
wire donut baskets are fantastic. On the WSM I'll just have the bottom grate on and stack these crosswise to each other several high.