The are some adjusters available that are slotted in 1/8th" increments with a spring loaded detent set screw. There has been some debate on the legality. I think that issue is beyond silly.
Ride heights on asphalt do not really change on a good tight car with fairly fresh components. Also when you raise the car in the shop and make adjustments, make sure when you set it back on the floor that the shock seats in the adjuster. Many times I will set a car up and the shock nut will hang on a shock top. It may not pop back in until later when you load it or possibly race it. Taping the adjusters is typical. make sure ALL of your ball joints are tight, the spindle cone bolt is tight etc.