Hi Keith,
Oh it's gorgeous! If it were mine I wouldn't paint it at all... just do the mechanicals, deep clean, and give it a wipe-over with lanolin or similar as it goes back together. The next person can paint it if they want to.
But silvers: ever seen a line-up of restored veteran Triumphs? All silver, but not quite the same silver.
The problem is the way old silver paints change as they age, so trying to guess the original colour is fraught. Anyway there is lots of chat about appropriate colours for the many bikes that used silver as the main tank colour, e.g. Douglas
https://www.douglasmotorcycles.net/index.php?topic=5846 The last time I had a silver tank painted (a locally-made "Bullock") I did use a silver with a little bit of fine "metal flake" in it. I was very happy as it looks good but doesn't sparkle too much in the sun! Triumph (and probably others) referred to their silver as "aluminium" - maybe it had some aluminium in it?
When I do paint, it's to stop metal going rusty, so I just use an etch primer topped by "epoxy enamel", both from rattle cans. A bit embarrassing, but I'm more interested in originality, well-functioning mechanicals, and history. And I'm rubbish at painting!
Cheers
Leon