At last I was able to test the Sony 200-600mm with flowers and insects... and it's very good. With extension tubes AF-S is very hesitant (probably because when shooting in a blossomed field you have lots of blurred things in the line of sight), but AF-C is still very quick and reliable.
Some samples, waiting for a complete review that I'm writing.
http://stoppingdown.net/diary/2023/06/19/#!/lightbox
http://stoppingdown.net/diary/2023/07/01/#!/lightbox
All shots with a flower have been taken with the SEL200600G; no extension tubes in the former gallery; 26mm of extension tubes in the latter (with the exception of the first two butterflies — the first three photos in the latter gallery have been taken with the Sigma 105mm ƒ/2.8).
