GOING CUSTOM
If you see something that you absolutely must have but it's thousands of dollars which you don't have, then make it custom, unless you want to make it bespoke in which case you should just stick with the one that's thousands of dollars.
Think of the Russian doll toys, how they fit into one another, Made to Measure fits into custom but not the other way around. The reason being is that custom means your body is measured and a pattern (which describes the individual parts which make the whole of a jacket, for example, once they are sewn together.) Custom also allows more fine tuned styling because of the often advanced customizations available, which can help to tell the whole story of the outfit, rather than being limited by a more generic template. If you want a classic design then it can be outfitted with quality of life improvements like additional inner pockets or an embroidery of your company's logo.
GOING MADE TO MEASURE
Selecting made to measure is a great option if you want something generic but also fits well if you're a somewhat easy fit, I tend to lean custom, not because of the fit but because being generic might as well be a big red X.
Think of made to measure like a piece that is designed on a perfect mannequin, now take that jacket and grow and shrink it's parts to accommodate your right arm that dropped two inches because you've been carrying a heavy bag on your right shoulder for decades, or your questionable posture. If you're an erect person with proportions that resemble a typical human adult, if there is such a thing, then made to measure will be better than off the rack and the template might be close enough to your body that you may not need to choose a fully custom suit.
THE CRUCIALS
Your body is the suit's hangar. I've always disliked clothing when it's not on a person, a mannequin is fine I guess, but when beautiful clothes are on someone who is hopefully also beautiful then it's a work of art. Fit the hangar. Most made to measure clothes have a base called a "pattern" and that pattern is adjusted to fit to your body better than it's original state. Your shoulders should fit well enough to drape the jacket past your body, letting gravity do some of the work, with the exception of some slim areas. Your "seat", or butt, is the important part of any bottom and it should be close to your hips but not pulling or tight when you sit.
