So the M5 is long over due for a proper tune up and valve adjustment. I bought the valve compression tool but do not have the shims.

Dose anyone have any advice as to the most economical may to go about buying the shims, buy a few of each size, etc. Is this something a average DIY can handle or better left to a pro?

Thanks in advance.
'87 M5
'90 325iX
'04 325xi