You would want to compensate for the braces in your measurements when having it made. Just to give you an idea, I had belt loops added and suspender buttons added to a dinner suit made when I didn't know any better. In total, I ended up having to have the pant legs let out about 2.5". The crotch obviously couldn't be let out; the pants are a bit tighter than I'd like there now, but I can still sit comfortably. However, I think everything would probably drape better if I had it cut the right way to start with.
The plus side is that the waistcoat now covers my (higher) waist.
Makes sense. At this point, I am leaning heavily towards a cummerbund. Given this, I may just decide to do side tabs (no belt loops) and skip the braces all together. I quite like the look of tuxedo shirt+black bowtie with a cummerbund when the jacket is off (which inevitably will occur) . . . when a proper waistcoat is worn that is low-cut enough to function as it should, I just don't like the look quite as much sans jacket (it's not bad, just not great in my opinion).
I'm a fairly short but muscular guy with wide shoulders and a pretty big drop/V-taper . . . I know sometimes people recommend a vest/waistcoat for people shaped like this; however, I think a cummerbund can look quite good and still create a decent "slimming" effect if done right. I don't know if they come in "sizes", but perhaps one that is on the more moderate rather than wide side would be ideal, one that would cover the waist without feeling as though it's encroaching upon my chest or anything.
Returning to the shirt issue, is there a role perhaps for a "bib front" shirt here? Does it hinge at all upon waistcoat vs. cummerbund, or is the choice independent of these?