For myself, I do not know how you could be asking such a basic question with an arena that is very large (which would indicate a great deal of time spent on this game).
But so you do not feel completely ignored: It seems to me the general consensus among people who have commented on the value of PR guys is that they are generally the least significant of the coaches you can hire. Their impact on attendance, as far as I can tell, has never drawn sufficient interest so as to be analyzed and quantified. Speaking on behalf of my own experience and I think reflecting the general consensus, I would say the biggest impact you have on filling the arena is winning. It is possible, of course, to change ticket prices, and the impact of that on drawing fans is significant, but that is a separate decision from the PR, and one he does not affect (as far as I know). Quite simply, win, and you will (eventually) fill the house -- lose, and people will stay away in droves, regardless of the advertising campaign the PR man generates.