UAS aerosport Bag Coil Ring Height?

[Rippin6Gears]

So reading, I didn't find much on aerosport bag install on coilovers besides compressing the strut and messuring a 4" gap. Then I read guys measure 4" of strut body 4" of the piston shaft. I just want to do this right the first time.
Little confused on where to put the height of the lower spring perch ring on my coilover, of course these don't have a large piston range of compression either. Currently the ring is roughly 2" threaded on the strut body...

[ncp91]

The way I have mine setup on my Yaris is the collars are 4" down from the top of the strut (where the tape measure is resting in your photo). So when the bag is aired out the top of the bag is resting on the top of the strut, and I air up to make the bag the same length as the springs that were on the Megans before.

[Rippin6Gears]

Well yeah I saw a picture of someone doing that so 4" down on the threads, these are actually BC Racing not Megan coilovers, since the cougar/contour don't have really much options I had to get these from UK. I don't want to get the correct setting so my strut shaft isn't maxed out nor is it bottomed out all the time. Trying to find the happy medium is what am trying to accomplish.

[ncp91]

If that's the case I would put the top collar 2-3" lower than the top of the strut. That way the bag would hit it's bumpstop before the shock bottomed out. Wherever you set the collar just figure out how much pressure it would take to get the bag to the same length as springs that were on the coilovers and you won't have to worry about maxing the stroke out.