I used 12.5W (by mixing 10W and 15W 50:50) in my MC21SE forks, and it was perfect for me. I am 90~92kg, depending on what I've had for tea and if I've had a crap!
Removing the airbox will dramatically effect jetting. Don't even begin to ask me what jets I'd recommend though. There's no reason why, with careful jetting, the bottom-end and mid-range should suffer too much. My 21 is very strong and smooth with just pod filters, and StephenRC45's MC18 was too, but that's gone back to fairly standard now.
I would definitely recommend fitting the correct flywheel for the PGM.
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Andy.
NSR-WORLD.COM
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