It depends on the height of the front of the control panel, the length of your forearm, and the height of your elbows above ground when playing. Your wrists should be straight to slightly bent down for "most ergonomic" (but feel free to do what you want).
CP height and forearm length are self explanatory. Height of you elbow is influenced by your shoulder height, length of upper arm, and your "game stance". Shoulder height is influenced by your overall height, length of neck, "tallness" of head, and "game stance". As you can see, overall height, what lots of people talk about, does have influence on the angle you want, but IMO is highly effected by other factors. I know of a 6'3" guy with long arms who likes to stand one foot forward and bent, other foot back and straight (almost like a calf muscle stretch), which results in elbows lower than mine; thus he likes CPs lower and/or more tilted than I do.
Sure, height of CP and CP tilt influence your stance, but since you're BYO, you get two set those to your "perfect stance."
The attachment, below, is drawn with two "game stances" (abcd & efgh), two overall heights (abcf & cdgh), and two upper arm lengths (aceg & bdfh). Since the angle matters on the ratio sizes, a person with a 36" elbow height, 38" CP front height, and 12" forearm would want the same angle as someone with a 42" elbow, 44 1/3" CP, and 14" forearm, assuming both like the same wrist bend. (Translation: there is no scale in pic, and they're just for illustrating what I'm talking about.)
BTW, dudes in a) & d) better lower their CPs, and h) should raise the CP.
