Turned out to be a tricky situation and took a fair amount of time. The tabs on the end of the mounting arms had to be bent and the bushings they attached to had to be shortened close to the weld to achieve proper alignment fore/aft and laterally. Ended up with the required zero degrees fore and aft but off 0.2 degrees laterally towards the pilot's side. RWI tech support says that is acceptable.
I used Dick Cannon's suggestion to place a piece of graph paper in the engine support ring with a plumb bob attached from the square drive tube above.