For what it's worth, I thought I'd bring up this old thread to report that the 3G Eclipse nozzles can be made to fit the GVR4. Just put a set on 56/1000.
MR322201 - Left Nozzle
MR322202 - Right Nozzle
You need to take a hammer to the reinforcement on the bottom side of the hood, because the bottom of the nozzle is designed for the hose to attach at a right angle, and unless you dent the reinforcement a little bit right where the nozzle comes through, it's too tight for the nozzle to fit properly and flush on top.
Other than that, you might want to have some 3/16" ID tubing around, because you have to re-do the hoses a bit. The hoses are probably old anyway, right?