I dont quite understand your point.
You set the koni yellows at the lowest perch.. then u set the sleeves at their lowest perch.. which are like 3.5" drop..
At the moment my sleeves are probably 2/3 from the bottom. So i can go lower!! :P
You dont entirely know if they are the exact height, but i just count how many threads there is from the bottom. Its pretty simple.
The clamping mechanism as u call it is really good. If you look around or search about ground control.. they are basically the only ones ppl recommend other than skunk2.
Heres a link defining coilovers in general.
http://www.norcalcrx.org/tyson/coilover.html
