You should have a set of spacers. 6mm and 12mm thick, plus a spring seat(perch) and plastic pieces to locate the spacers and spring whilst reducing the metal to metal contact .
For the different ride heights, arange the stack as below:-
Lowest- perch, plastic, spring.
Perch, plastic, 6mm spacer, plastic, spring
Perch, plastic, 12mm spacer, plastic, spring
Highest- perch, 12mm, plastic, 6mm, plastic, spring
You would also be using the original rubber spring seats top and bottom, below the perch and above the spring.
Once you have settled on a height, set the shock length...
With the car on the ground, measure from the arch to the wheel. Jack the car up by 50mm above the measurement you just took. Now, set the shock absorber length so the lower damper bolt lines up spot on
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