From what you've told us, for the sake of a $5 bearing and a couple of hours work I would be changing the spiggot bearing first. Wouldn't be the easiest thing to change with the engine still in the car, maybe remove the engine/box in one, split and change spiggot and put it all back in.
Incase you're not aware the spiggot bearing is in the back end of the crank. Easiest to remove with wet torn up news paper! Lol
Also if you have a 180mm (4k) flywheel then you just need a regular k series clutch kit.