When RSVPs do not apply

So I am planning a party for 100 people or 50 people or maybe 300. I really have no clue. Now this creates some issues. Well, this creates a ton of issues. Like, that I have no clue. But nonetheless, I have learnt what I need to put on a dinner of this size. Whatever 'this size' may be. Such as:

1) If I run out of anything, it better not be bannock
2) Need lots of jam for the bannock I cannot run out of
3) Although very tasty, organic whole wheat bannock will not go over well
4) There is not a "bannock makers" section in the yellow pages

At this point, all I know is that I have an order in with a lady and it is supposed to be ready at 11 am Sunday morning. Yes, that's right...2 hours before the meal. She told me she isn't going to start cooking it until Saturday night. But no worries, she says she is a fast bannock maker. So all I can do is put faith in this ladies ability, because damn I am scared of what the response will be to dinner rolls!