While thinking about what to do next and where to mount stuff on the firewall, I realized not everything going through the firewall will have or need some trick fitting. Some stuff can get by with a simple grommet and a stainless steel protective shield over it. (typically wires). I used a few of these shields on my RV build. They're simple and light and do the job on Cessnas and Pipers for decades. Probably good enough for me too. They're about $12.50 a throw from Acft Spruce (plus shipping), but anybody can do that. I recalled reading an article by Tony Bingelis in an EAA publication about how to make your own shields (for less). Tony used a socket and a larger piece of steel tubing to telescope the socket into with the stainless sheet pinched between, squashed in a giant bench vise. I did about the same, except I used a pair of big and little sockets squashed in an arbor press. The bigger socket is twelve-point, allowing a slightly larger small socket to fit into it. I had a bunch of leftover SS scrap from the firewall fabrication, so I cut some generously sized pieces to stamp the shields from. First step just squishes the smaller socket into the SS sitting on top of a scrap pine 2X4, making a round dent. Next, the dented SS is carefully centered on top of the larger socket and the smaller socket replaced in the dent it formed in step one. Placed in the arbor press, time to squash again. Pressed about an eighth of an inch into the larger socket forms about the size dimple required to cover half a firewall grommet. It's pretty wrinkled up after step two, but plenty of malletizing with a small ball-peen hammer makes them mostly flat again. Sanded the edges back to get them in more of a pleasing and eye-catching shape before punching out the attach holes and a center hole. The center holes will be widened as necessary depending what is going through it's respective grommet. Oh yeah, Tony calls for a small disc of baffle material to be placed under the shield on top of the grommet when it's screwed in place as well as some sealant if the grommet doesn't tightly fit the wires (or whatever) going through it.