Wow! That before picture is very exagerated.I suppouse that kind of rockers are harder to center.

However ,what do you guys do for determining that it is correctly side centered? I mean on roller tip rockers.

Mine seems to be ok and i haven,t done anything.The valve stem is in the center of the roller tip,it can vary the 0.015 of side clearance,of course.

I use a magnifing glass to check it and seems to be ok.I don,t know any other method for this...
Besides, in the Hughes instructions sheet,they say that centering is not mandatory and sometimes some offset can be allowed.