Note: On Rega turntables spacers should not be necessary unless you are you using an exceptionally deep bodied cartridge from anotherr manufacturer.
Arm height or V.T.A adjustment can be a controversial subject. Rega believes that the integrity of the arm fixing onto the arm mounting board is much more important than the questionable facility of arm adjustment. The arm should be reasonably parallel to the record surface or slightly lower at the mounting. The only time a spacer is necessary to raise the arm height is if the rear of a cartridge is hitting the record whilst playing.