It depends on the clothing line. Some have a lot of options where there are different features to suit different body shapes. Others are all the same.

So to solve the problem, first you have to care about it (which Steve probably does not) and then you have to know various ways to solve it (which Steve probably doesn't either) such as shopping different lines or hiring a tailor.

Now if Tony wants to take Steve to a posh event and have him look good it'll be, "Here's your ticket for the tailor; you take his word on fit and he will take your word on colors, that's the deal. Just go down to the garage and Happy will take you there and back again."