Just to say that the real thing was indeed, a very high gloss (although units would let it get dirty and dull in the field), and of course mud and the usual predations of terrain, dust etc would inevitably prevail.
I found that even after a gloss varnish, the results were never that shiny, yet with a bit of weathering the gloss effect could still get the right sort of finish as it were; see for instance, my Charioteer:
Arguably(!) What I’m suggesting is that a satin varnish might not do the trick.
The Champ is from Accurate Armour.
Just as a reference you might like to view this clip showing a Saladin:
Armoured Cars (1959)
not that I’m implying you’re not aware of the gloss finish I assure you(!)
As it happens, I have a Centurion model finished in the treal thing - Deep Bronze Green; I snaffled a 5 litre tin of the stuff when I left the Regulars; it went on like a dream, brush painted as back then I had no airbrush, and reflects (no pun intended) a slightly different almost bluer shade, but still high gloss. I’m not too sure where it is at the moment but I will try and locate it. Not much more authentic than that, but of course, I knew nothing about scale colour back then.
Regarding SP Air Defence, the UK never seems to get the mix quite right; tracked Rapier was a dream to operate or so my Gunner friends tell me, but of course, there were no guns to add balance to our AD assets. Back in the 60s/70s we had a gun/missile mix with the L40/70 (but not SP), and the Thunderbird - a large AD missile but a static piece of kit. Then we seemed to dick a round a bit with first, 20mm on FV 432, then 30mm on a Chieftain chassis - neither of which went into service. Of course, the air threat has changed considerably since then.
These latest iterations seem to be all things to all men - perhaps they will prove their worth if, if they enter service.