Yeah, my right arm is almost an inch shorter than my left and my right shoulder is about half an inch less long than my left shoulder. RTW is hit or miss. The length is easy, I just have the right sleeve shortened more. Shoulders are a bit tricky. Some RTW is doesn't make a difference, in others, it causes divots. If it causes divots, I avoid as the corrections generally cost upwards of 50 dollars and the tailor that knows how to handle them works an hour away from me.
The easiest thing to do is just have everything made for you. It took my current tailor about a jacket and a half to get my shoulders just the way I wanted them (at least as far as fit).
For lower shoulders (mine are even, it's just the size that's different), I think there are things you can do as far as adding/subtracting padding. And arm length is just a matter of getting the sleeves shortened, a fairly routine operation.
Thanks much. Right now I just have the sleeves done, and if the shoulders don't look right, I don't buy it.