as an aside, i have found that shoulder measurement is the most flexible measurement, as there are many many ways to cut a shoulder, and the seam can fall on different parts of the shoulder and still look great depending on the cut. all my shirts and jackets have various different shoulders measurements, varying up to probably an inch and a half. i find that the waist and chest measurements are much more fixed, as your waist and chest are the size that they are, cut does not change that. but, with the waist and chest, you can often take it out by half and inch or more depending on how much excess fabric there is, and you can certainly have it taken in. any good tailor can do that pretty easily. tl;dr, dont dissuade yourself from koppage simply based on measurements without putting some thought into it.