Adjust front strut height

Here is a modification to raise the tail a few inches. This is to counter the changes of diameter of the nose tire. Don't use it to compensate for worn out rubber donuts on the MLG.

alphaaviation.com/ercoupe-main-landing-gear-spacers/

'46 Coupe 415-C with the Double Arm nose gear assembly. 
The airplane is not level: I am about 2" lower at the tip of the vertical fin.
How do I adjust the gear? Spacers on the main gear? Can I lower the front gear?
Also, I get some shimming in the front gear at times when I land - checked tightness of all components in the front gear assembly and all of them are tight, except the collar round the strut, which has a bit of looseness - but I cannot figure out how to make it go away. Thanks in advance for your help.