Here is what we do with our large events.
1) Give the customer our menu (w/qty & prices). If they ask for "suggestions/advice", on qty, we freely give it to them. Then we ask, "How much of each would you like to order?"
2) If you normally get 20 - 4 oz servings from a full size pan, and a 4 oz size is what they ordered, then your number of pans calculation is close (it is actually 16.5 pans of each). (unless you choose to use Common Core math for your calculations :mrgreen
330 is a lot of people to feed. We would "suggest/advise" the 4 oz serving size to the customer since that is a very nice helping of each. Of course we would also inform them that this does not allow for some people "loading up" so they might want to buffer their order up some to allow for that. Be sure to have the customer make the decision on "how much" they are ordering and be sure it is plainly laid out in your contract. (you do use contracts don't you? :wink
3) If you do not have, or have access to, the required equipment to transport and deliver the food at food-safe temps then the cost of you renting the proper equipment is an extra fee that you will pass on to the customer for this event. We usually add such items in along with our vehicle fuel, etc as "delivery costs". This cost is NOT an overhead cost figured into the "costs x 3" formula if you are using it. This is an actual separate cost specific to this event.