FROM WHICH YEAR DOES IWC APPLY LUMINOVA INSTEAD OF TRITIUM?

I'm interested mainly in the Flieger- and GST lines (3706, 3707 and others). Both approximate case number and production year info is highly welcome! My estimate is cca. 1999-2001.
Thank you in advance for your kind input!
Best,
Robert

Hi Robert
I hope this helps:

My
GST Chrono 3707 - serial 27875has Tritium (+/-2000)
GST AT 3536 - serial 28797 has Luminova (+/-2002)

Thank you Mark for the info, in the first round this helps: my plan is to buy one of the mentioned watches for my daughter (for finishing her high-school) who was born 26-09-2000 so the watch has to be "made" in the first nine month of 2000, approx. case numbers between 2730xxx and 2775xxx. I was hoping this series was just made using Luminova but your 3707 (278xxxxx with Tritium) made my decisions more complicated... 

That’s really interesting Robert!
I gave the 3707 to my daughter as a graduation gift and she wears it daily :o)
She morning is 21 now.