Personally I would look into getting fit at a Titleist Thursday, if there is a location in your area and one available for you to attend. I think there is more product knowledge and shaft/club options available for you to try out over the big box store fittings.

At 6ft 5ins , your certainly going to need longer clubs, probably +1 inch and have your lie adjusted. Id 100% recommend some lessons as well. I think it would be daft go for a fitting for new clubs without a couple of lessons to make sure your holding your club, swinging it properly. It will help with you Stance and Set-Up , i think once youve have these basics it would make more sense to then go and get a fitting for your new clubs. I recently got fitted for the AP1 718's and so glad i did. Id do what Ken recommends and look into a Titleist Thursday fitting. They have far greater knowledge and more shaft/club options. My expericence of normal stores is they have limited shaft options , and have limited length options especially for guys like ourselves, ( Im 6ft 4ins) I also feel like the normal stores would sell you something because it was in their limited stock just to get the sale even it it wasnt quite the best for you. Book a Titleist Thursday or go visit another Golf Course pro shop that sells Titleist and give them a demo. If you like them go get fitted by Titleist before you buy them. Hope that helps