Wooden shims from home depot will do the trick with the shelf. Don't start putting junk under the feet of the table or you are asking for a table that's never right.
Need help leveling a Rega P25
I just installed a Rega wall shelf for my Rega P25, and though I tried to be careful, it is not 100% level, though it is pretty close. The right side and back need to be raised slightly. I've never dealt with audiophile tweaks before, and I'm wondering if there is something better than, for example, simply putting little pieces of cardboard underneath the rubber feet that need to be raised. Any suggestions?