I'm having a little trouble visualizing all of this so, please bear with me.

-A- measured as a plane becomes your 3D alignment. -B- measured as a cylinder becomes your axial alignment. -C- measured as a cylinder then, intersected with -A- becomes the datum. Construct and callout perpendicularity between -A- ,-B- and -A-, -C-. -B- position allows for offset measurement to -C-.

Jeff