I purchased stock lights from Orielly's when I was in Fla. I am quite happy with them. I do have some tech aid . I set the old lights beside the new ones and counted the number of threads on the adjusting rods, setting the new lights as per the old ones. This gives you a good position of the light and it will be very close to the correct adjustment if your old lights were properly adjusted. Once installed it is very easy to adjust them as they may need little or no adjustment .