Do you know what fit you want on the bike? If you do, then it should be easy to draw out what you wish to do. If you don't know what sort of fit you like, you might wind up with something that fits you, but you don't like the fit it gives.
That's sort of many peoples downfall when the get a bike. They buy bikes that aren't made to give them the fit they want even though the bike can provide them a proper fit for their size.