If by "most drop" you mean the thinnest, then yes. The pads are merely meant for fine-tuning. I've seen two identical SRTs have different pads from the factory, if that tells you anything. Keep in mind that by going with the thinnest pad, your drop will only be as much as the difference in that pad and your OEM. Springs perform the drop, pads simply perform the insulating and tweaking of the spring.

OEM, I had the 5MM in the rear and the 13mm up front, or for the dot-counters, 1's and 3's.

After the installation of cut springs, I still needed to drop the front just a hair to make the rake look proper. I went with a 2-dot pad in the front and it fixed the rake.

As for a description... not sure what you want. It's a black rubber doughnut with a recess for the spring to cradle into. The doughnut varies in thickness. Roughly 4" in diameter.

I'm sure someone somewhere has taken a pic of the spring pad, but I personally have not.

Google might be your friend, if all you're seeking is a visualization.