Due to acquiring a used empennage with the wings I bought, most of which I replaced, I ended up with the old white fairings and also new gray ones. As I mentioned before, the white ones are lighter, so even though they're a bit thinner and seem a little less robust, thats what I elected to use. The exception is the upper rudder fairing. The white one was about 1/2" shorter than the gray one and I was going to have to build it up significantly, so I used the new one up top on the rudder. The bottom fairing has a molded in light cove, but there isn't room inside for the threaded plate that came with the nav light. Vans has you fabricate a mounting base out of 1/8" aluminum, tap threads into it, and pop rivet it externally to the light has something to screw into. Pardon me, but how much more hillbilly can you get? I played with this for 2 days including research before coming across a solution somebody else had successfully with. Basically, lay up 2 piano hinge eyelets in flox inside the socket, then drill them and tap for #4-40 screws. That worked great and nothing cobbled together on the outside. I weighed it after and the whole thing including the light is still 2 oz lighter than the gray one just by itself. Success! I'm following the Vans drawing for routing wiring to that tail light, and it requires a CS4-5 pop rivet to secure a wire tie mount to the fwd face of the rudder spar, but there are exactly zero of those in an RV7 kit, so I had to order a few. I won't permanently install the fairings until thats done. I also took some time to get the gap right between the V/S upper tip and the rudder counterbalance horn. Vans doesn't specify a specific gap for this area, but on the elevators it's 1/8" so thats what I was shooting for here as well. I had the closeout on the aft face of the V/S cap a bit proud, an that opening wasn't quite big enough, so I block sanded it down and once it was right, I repainted it with dupli-color rattle can primer just to protect it from uv for now. The side profile doesn't quite match. I haven't decided if I'm going to try to fill that with micro, or just let the paint shop deal with it.