my 906, 907ie and M1R all state 180mm

When I did my forks is what I put with a SAW 10W oil and I am quite happy with it.

Be wary of different brands of fork oil. It isn't always what is says on the packet. I found this out the hard way when I fitted an Andreani fully adjustable conversion to my Scrambler and I was wondering why the forks were hard as feck.
There are huge the differences in viscosity measured as Centistokes @ 40ºC between different makes of oil all allegedly the same SAE weight.
I can't upload the file with this info as a PDF and as images they are too large, at 800 pixels high they would be unreadable. I'll have to think of another way.

Derek, email it to me.

No need Gerhard. I've found the same info on an Australian website :https://transmoto.com.au/comparative-oil-weights-table/

I should have used Öhlins 1309-31 but found it very difficult to find so I used Silkolene PRO RSF 5wt thinking it was a similar weight. It turns out that the Öhlins has a viscosity of 19 cSt @ 40ºC whereas the Silkolene is a whopping 26.7 cSt.
There are similar discrepancies across many manufacturers products.