High altitude

[greybeard_52]

 

It seems that the Luftwaffe in Africa needed to intercept at high altitude. Proof of this is that 544 F-4 / Zs were built versus 576 F-4 Trops, according to Wikipedia (but does not specify if the former were all used in Africa). I would therefore be curious to know which Allied aircraft flew so high that they required the use of the GM-1 to intercept them. I would also like to know which staffeln employed the high altitude version of the F-4. Or, I wonder, was it a question of the rarefaction of the tropical air? I tried asking around, with no success.
The above seems to be strengthened by the creation, by the TF, of "Alta Quota" versions of Macchi C.202, of which I have never found mention in specialized literature. I would therefore be grateful to anyone who brought historical evidence or to TF itself if any of them who participated in the development of these special versions could explain to me the historical principles and related sources used. Again, I would be extremely pleased to know which "squadriglie" would use it and when.
Thank you for your time.