Haha fair enough but I do appreciate everyone's input here as I am somewhat a suit noob and definitely new to spier.An honor to be graced by your 3rd post ever in the 8 years you're in SF.
Get the short. Don't listen to most of the guys here as they'll just recommend Regular no matter what your proportions are.
It's just confusing as numbers would seem to indicate 40 but suit supply 38s fit like a glove with only needing sleeves lengthened. Doesn't help spier lists actual circumference measurements and ss lists widths. Both are fine to use but it makes it harder to compare.