There are a lot of factors here and when I read your post I get tons of questions going through my head because the post was pretty vague.

A host generally ensures that everyone has a good time and directs the events of the evening, arranges proper location, comfortability of the guests etc and/or takes care of food, cleanup, serving etc depending on the party. To dump all that on one person can be taxing. This is all my opinion of course.

Im curious as to /why/ youd want your sub to host and not just do it yourself. What kind of role would you be playing at the party?

Im also curious as to what kind of party it is exactly, Im thinking along the lines of play party but Im not sure, I can only assume. In which case as her dominant, Id think youd be hosting.. as for limits, are ppl allowed to play with her or is she allowed to play with them, are they only allowed to watch, is she serving only, Not sure. Might want to clarify to get advice geared toward your situation.