R6 rear shock on the FZS600

[kebab19]

Considering this myself are the parts available anywhere ie top hat bushes, spring spacer dog bones etc?

Also the Fazer 600 spring is 823lbs, does the R6 shock offer resistance via the gas? the quoted spring values are less than 823lbs?

I am a big lump and according to spring calculators I need 1.0KG/mm fork springs, so i expected to have to increase the spring rate at the rear?

Sorry if i am asking silly questions.

Hello.
Not at all, the only silly question is one that isn't asked.
The conversion parts are not commonly available, apart from the dogbones. I could contact my metalwork fabricator if you need the parts, but (like everything in 2025) nothing's as cheap as it used to be...
A direct comparison with the standard shock's setup is fairly pointless, I initially found that despite the vast difference in spring rates, the standard 525lb R6 shock spring felt almost the equivalent of the OEM shock setup, which was a real surprise at the time. 
I've converted about 30+ shocks and from memory, the largest spring rate variant was for an 18-20 stone rider setup. If you're bigger than that, then we're into unknown territory, but the internals would probably need revalved so no longer a cost-effective option.