I suppose it also depends on how you want to look.
I have a comparable drop (12-13"), but I don't want to walk around looking like it. I tend to have my jackets very generous around the waist, pretty much how they will be if they fit my chest, shoulders and arms. Sometimes I have found an "athletic cut" and either left it as is, or had it altered to "fit". I tend to be conservative about the altering, since I want to look like I have an average drop. Wearing a jacket that is way too big around the waist makes me look like I have the typical middle-aged paunch, and I fit right in.
When I inherited some suits and jackets I had an excellent tailor alter them. I don't remember a discussion of how close I wanted them to fit, but he seemed to understand that I wanted a conservative appearance. Some of the pants he could not take in enough at the waist. To the extent the suits could be done, I ended up with them a bit more fitted than in retrospect I would like, but wearable.
The bigger problem comes with shirts and trousers. For shirts, which tuck in to the pants, there is a huge amount material floating around the waist. With a jacket on I can tuck the excess behind me, but it is still noticeable. It looks bizarre if I have the jacket off. Trim fit shirts that fit my neck make it look like I am wearing spandex over the chest and shoulders, if I can get my arms into them at all. Right now, way too cheap for MTM let alone bespoke, I get oversized trim fit shirts. They then do not balloon too much at the waist, fit the upper body, and are mainly just too loose around the collar.
Trousers, here is where you might find MTM or bespoke worth it. Pants that fit my waist look like tights over my thighs. I get double pleated in waist as big as I can that can be altered down to close to fitting. They are still a couple of inches too big at the waist, but that does not look as odd.
The main secret is rarely being seen without my jacket, which covers up most of the fit problems. Has the benefit of making me seem more "formal," with is fine in my workplace.
Just remember, the designs of suits were made for people with typical builds, or very slender models, with little muscle mass. If the suit really fits you, it will not look like the way suits fit on most people.