The first revision we made was going from a progressive design, to a dual rate with linear working rate design.
The current springs, some are different than others when installing. For example, the handling GT springs install a little differently than the drag, and the SP009 Performance Springs.
As for the angle of our springs, there is a reason that they are how they are. Several variables to the design choice are, compatibility with aftermarket strut perches (some have different angles than OEM) - and some motion ratio characteristic stuff, which I do not feel like explaining in depth on a public forum.
I know of 2 other companies specific springs that are almost exactly like ours when installing.
With a compressor, like we instruct in our install instructions, it is very simple.
For example, if you have an issue with it like this:
...then you tighten the right side compressor a little more. Install USM, TQ it, then release the spring into the USM.
I may be a little bias because I do/have installed so many, though.