What clip pos?
I think that N8Rx is very similar taper to N3Ex, only a half a clip, or clip richer.
IE N8RH#4 = N3EH#3.5/#3
(Can't confirm this, just a quick google turned it up)
Update: Confirmed in Yamaha Manual
N8RH (Rich)
N3EH
N8RW
N3EW (Stock)
N3CW
N3EJ
N3CJ (Lean)
So judging from that I already know that N3C is half a clip leaner than N3E, so N8R will be half a clip richer. The last letter is the diameter richest to leanest H, W, J. FWW I've been running the N3CJ#2 in my 300.