Extra width should never be allowed in the back of the crotch; better allow it over the hip. Allowing extra width in the crotch is just like allowing extra cloth on the front of the armhole,—it makes the whole smaller.
The trick in altering any garment is to first ascertain what will make it worse, and then make the contrary alteration. Example: If a pants cuts in the seat pinch the top of the sides together, which will make it worse, then put a wedge in the top of the side seam, and reduce again in the center of back.
If you find your pants too large or too small do not change the drafts, but take the measure smaller or larger, as the case may be. Take the seat measure close, like measuring a barrel, and have no slack.
Your customer’s pants waist must be as large as what he measures when he is in a sitting position. A man’s waist in that attitude may expand anywhere from one to five inches.
A waist-band made according to the old teachings, as three-fourths inches more than half measures, will not stand the test, and is a delusion.
If a customer tells you to make his clothing very large, he means that it should not be too small. If he instructs you to make it tight, he means that he wants it not too large. Either will be returned if it does not come up to his actual wants.
If a customer gives you a thousand and one directions, take them all in, study what he wants, or what he really needs, make his garment accordingly, and he will usually turn out as a customer not hard to please. But if he tells you that you are the tailor; that you know best what he wants; that you shall make it according to your judgment, do not think that he will take anything, for he will usually turn out to be a very particular customer, who expects you to know your business.
Remember that old men require a larger seat—that is, a larger back slope in their pants; because, in aged persons, the seat actually caves downward, hence old persons grow shorter.
Give boys considerable straddle in their pants, not only for comfort, but for the more important reason that boys should never have any pressure on their sexual organ. Thousands of young men go to their early graves because some silly tailor made their pants too tight, by which they learned to abuse themselves.
Better talk half an hour with your customer after he has been measured, in order to observe his build, rather than to spend half a day in altering afterwards.