Paint cross references

Has anyone used Testors Panzer Gray or Tamiya German gray in place of the SP Lark Dark gray on painting their helmets? I was at the hobby store today and was looking at them and both look like fairly close alternatives and I was curious if anyone here has used them as a substitute. I did some searches and the Panzer came up as a possible alternative to the SP Lark on AFFO$ paint thread.

Also, I thought there was a paint cross ref chart floating around here somewhere, but I can't find it. Possibly another forum, but I thought I'd ask.

try these 2 :
Color Match 1.0
Ultimate Model Paint Conversion Chart - Paint4models.com

Ahhh, that second link was the one I was looking for. Thanks darth z! Panzer and German are equivalent which I pretty much figured, but apparently SP Lark Dark Gray stands alone with no close matches.