War: Gravity bleeding doesn't seem to work with the clutch. It's a lot harder to bleed I think because it has a master and slave cylinder, where brakes don't have a slave. That may be the big difference.
Kennedy: Can you tell me if you have the SB1010 in the front? They are the 10M x 1.0 size. I have four of them that I bought for the brakes based on the Pathfinder fitment.
I already figured out the rears are smaller just by looking at them. Although I'm not positive because I haven't actually pulled them, they appear to be the same size as the clutch bleeder or maybe one size larger.
So, I'll tell you what size fits in the clutch.

The SB7100 (7M x 1.0) fits the clutch slave. It's a little longer than the stock bleeder but the threads are right and it works great.
I also have an SB125L (8M x 1.25) that I can try in the rear brakes. Just need to find more time! I'm pretty sure the rears will either be this size or the same as the clutch.
I'll let you know when I figure it out. You have to share too if you get the answer first!
Could someone tell me why Nissan can't just use the same damn size atleast for all the brakes? Sheesh!