WHICH SPRING PADS SHOULD I GO WITH WHEN LOWERING?

Just installed H&R springs on my 1999 CLK 320 coupe. The rears are nice (1-finger gap)but the lowering in the front is hardly noticeable (about 3 fingers). Got stock shocks and stock spring pads along with 18' rims. I want to do the fronts over with different pads. The dealer said that my car comes stock w/ 9mm pads, and those are the thinnest pads they've got. They were confused as I was when thinking about whether thinner pads help lower the car, or thicker pads lower the car by compressing the springs more. Other pads come in different thicknesses with the thickest being 21mm. I want to lower the fronts by another inch or so. Is that possible through changing the spring pads alone? If so, which ones should I use?<br>