I'm looking for the angle it remains steady at regardless of aircraft pitch . . . .
That can't be! Are you saying that the bogies move in response to pitch? It may be, like the Lockheed C5, that they move slightly in 'heading' to allow for landings with yaw on - but pitch.
Why would they do that?
PS. Having said that the C5 bogies allow for drift/yaw on landing I've looked it up and - no mention. I didn't dream it!
http://www.baseops.net/c5/gouge/Section1.pdf
PPS. Thank God for that. Found it.
The C-5B dispensed with the C-5A's complex crosswind landing gear system.
PPPS.
The C5A landing gear bogies may be set at an angle of as much as ±20° from the centerline of the aircraft to simplify takeoff and landing operations in various crosswind conditions.