Cable and housing is included with the shifter weight. The chain weight (for the X9) is claimed, what it says on the box. Although I will not be running very many links (33, 11-23)

 Then your good to go

 Parts I'm taking off (like chain, old sprocket)..subtracting their weight from the total.

 x0 and x0 is high-end, PG990 is high-end. X9 and PG950, not so much. But getting close.

 well you might have some weight savings with the 950 going to the 990, but i think there's a one piece aluminum spider for the first few rings and that wouldn't work with your 6 cog setup... x9 vs x0 shifter can't make much of a real weight difference at all..?

 Dremel solves the carrier problems. X0 shifters apparently feel a lot better. Don't know about the weight difference.

 oh, i thought the internals for the x0 and x9 shifters were the same, apart from a carbon cover and bottom lever reach adjustment. oops!

 After som investigation, they are. Difference in weight seems to be negligable. The adjustable lever is apparently more conducive to customization though, and people say it's just ....better. Not sure what to think, I do know I'm a parts whore though.

 Does it seem about right? Seems a little low to me. With a high-end setup, the weight added would be closer to a pound clean, but you've gotta make do.

 Not sure, to be honest.

 No. But it's only 605g (tentatively, without the final high-end set-up) heavier than SS, which is a fair bit less than I was expecting.