Due to add on pack coming from different source, and made from different plastic than the full base set... I was planning on wait to receive the PBT, then match as best as possible that with GMK. It would make a small delay, but I think it would ensure the best result with the smallest possible color variance instead of going on color blindly.
So, now just waiting on quote for the ISO/1.5/etc add on pack... and EDox add on from GMK. I sent email for it again today so hopefully I will hear something back soon.