Try what's available, and see if a stock bike fits you. Or can be made to fit.* If not, you're going to fit a custom better, because it can be made to fit you.

*One of my pet peeves is the lack of fitting going on when most bike shops sell most customers a new bike. Most manufacturers have reduced the number of frame sizes they are producing, based on the supposition that compact frames can fit more "sizes" with long seatpost extensions and stem changes, and with the change to threadless stems with removeable face plates. This would work great if every LBS-sold bicycle went through a 10-30 minute process of adjusting the seatpost and changing out stems to fit the buyer. But most LBSs I've seen don't have a wall of stems for fitting, they have six stems with garish colors, and charge high prices to fancy up an otherwise "dull" bike.