I like fhe idea of a sack suit. The problem is that in am quite thin with relatively broad shoulders (30 inch waist, 36 inch chest, but something like 18-18.5 inch shoulder). I have to size up to a 38 to find anything that fits, and Im a bit worried that the proportions of a sack suit would make it impossible for me to satisfactorily tailor a jacket that's a full two sizes up. Most of the size 38 jackets I have seen are around 40-41 inches in the waist. O'connell's for example has nine inches of ease in the waist. Realistically if I were to tailor a sack jacket, I would end up at minimum with 7-8 inches of waist ease. Because of my build I wear clothes with 8-10 inches of ease all the time and I think they look fine. This is true of my shirts. However, my understanding is that waist ease in a jacket is usually 4-6 inches, and i have found that something about suit fabric looks off when you have too much ease. Could someone clarify how exactly a sack suit jacket should look?…