What angle do you actually use? I've tried to position a split keyboard vertically, but found it difficult to press either thumb keys, or the rest, because of the angle between the thumb and palm. Consequently, I opted for something like 70°, and quite liked it (except it made the keyboard sound hollow).
I second the question about pointing devices. How do you deal with too high desks and/or the difference in height between the keyboard and the pointing device?