Hi Francis,
When I did prepare instructions I used Federal Standard (FS) chips to compare to photos.
I can't tell You exact numbers for Testors, Humbrol and other companies paints, but as soon as You (or someone else) have FS catalogue, then You can choose a closest to FS ones from the paints You have.
Happy modelling!
Sincerely, Alexey.
http://www.acemodel.com.ua (Europe)
http://acemodel.tripod.com (America)