U-Stem Verbs in Sindarin

Looking through Eldamo 0.6.9 as you may and I came across the Neologism echuinu-, "to wake".

Admittedly I have seen the primitive word ET-KUINU before, I always used the older neoligism **echuia- because I didn't believe that u-stem verbs existed in Sindarin: that either they had dropped out of use or that the -U- verb suffixes developed so late in the Common Eldarin stage that either they evolved to be used only among the Ñoldor and Vanyar kindred (as the Teleri lagged behind a lot) or that they evolved just after the split of the Eldar.

But let's say that they did exist in Sindarin:

1) Am I an imbecile and have managed to completely miss an example of a Sindarin U-stem?

2) The big question I'm looking to figure out: how in the blazity blazes might one hope to conjugate this thing? Would it go present singular like echuinun, echuinuin, echuinon, or what malarkey?

Here's to hoping that I'm not a complete imbecile,

Ríon Gondremborion, Ríon Gondremborion

The only possible example I was able to find is Noldorin dufu-; all other examples are from Gnomish or Early Noldorin. No idea on conjugation, sorry.

Thanks for the response!