Measuring ride height

To each his own.

The fenders would not be my choice as you are not setting it correctly.

If you first set the static height with the nuts loose and need to make minor adjustments down the road there is no need to loosen the pivot nuts again. If you are adjusting inches or more than, by all means loosen the nuts on the pivot first. If it had already been done correctly and that much adjustment is required then one must look for other issues.