Brad asked:

Does anybody know where to buy a good fitting for the prop and mixture
cables to pass through the firewall? Something more secure than a rubber
grommet that the manual calls for?

Brad, you might consider Aircraft Spruce. They have both metal and
fiber/rubber "eyeball" fittings for just this purpose. You didn't say what
kind of a Lancair you are building, but if it's a -P, you'll want to
consider the pressure loss through this fitting. The aluminum fittings with
rubber sealing grommets that Lancair supplies actually work pretty well.
There is no load on these when installed with the correct terminal hardware
and the rubber makes a pretty good seal...

Bob Pastusek