Just FYI, in my VNT 17 the #23 spiral ring is more like a c-clip. I'm going to remove it, put it where it needs to be inside the housing on turbine side. and see if the shaft slides in and snaps in place. That's what seems to be holding it out as it need to go much farther in to seat.
The c-clip does not need removal. Make sure you marked how the nut and cool side turbine are aligned and make sure when the nut is removed to put it back together the same way. The washer is there to keep crud from getting to the vane control and should be large dia toward hot side turbine. When re-installing shaft, you can push on the turbine side and the c-clip will click into position. The cold side turbine and nut can then be installed in the position taken off and tightened.
when you say C-clip, are you talking about the oil seal around the turbine shaft?
On the hot side of the shaft right against the hot impeller there is a short part that is about 5/8" or 3/4" diameter about 1/2" long or about that. This part of the shaft has a small seal farthest from the impeller and right after the seal is a c-clip. it's hard to see in the one picture (my appologies only phone camera) but I think the parts list calls it a spiral spring - on this vnt 17 it's not spiral, it's like a c-clip.
When you pull the nut off the shaft this c-clip holds the shaft in the cartridge. If you give the end of the shaft a slight tap, it pops out and the cold side impeller is free and the shaft comes out with the hot side impeller (I think it's welded to the shaft).
Installing the shaft requires a slight push and the c-clip will 'click' into its place.