I, too, did not bring my best swing but I could not be happier with what I ended up with. Keep in mind the full swing fitting is done in no more than an hour - that's driver, fairways woods, hybrids and irons and deciding how you want to configure your bag from top to bottom - but you will be working with some of the best fitters in the business!
personally, an hour is plenty. i've been futzing around with gear long enough to know when something works and when it doesn't. 2 swings, 3 tops and i know. if i had to rank the areas of full swing importance to me it's irons -> driver -> hybrid -> wedges -> fairway wood. i am so freaking pumped for that experience!