Simon,
The typical roll as a function of anti-torque thrust is evident, so that an OGE hover might have 1 degree more roll than an IGE, and a light weight hover as much as 1.5 degrees less due to the change in MR power and the ensuing change in anti-torque thrust to trim the helo.
For gentle yaw rates, the roll coupling is very low, mostly because the amount of thrust change to produce small yaw rates is very low, the moment arm for the TR in yaw is large, and the yaw rate damping is nil in a hover, so the thrust is only momentarily higher than trim.. For rapid yaw turns the roll contribution is substantial, but these are almost never used except in airshow maneuvers.
Roll is big in high speed lateral flight, due to both TR thrust and fuselage drag, of course.