CDM in middle of cd

[Mikelo]

To adjust focus offset properly, the CD should
be playing in the middle of the disc, but I am
not sure how to do it on CDM lasers. On KSS
ones it is fairly easy to do, but on the Philips
swing arms I can only guess very roughly. A
transparent CD audio would do the trick, but
I can't find any that are translucent enough,
to spot the lens from a safe distance and
angle.

Thanks!

 

[revell]

the top CDR from memorex spindles are transparant ones (without a writable layer) maybe you can use that?