...so much for waiting for the outer skin of the silencer and trying
it without packing. 
2kg of loose basalt wool, and a square meter of E-glass. (Both from Merlin Motorsports.)
See, there is a benefit to making this silencer a meter long! That's about three or four gentle wraps around the perf tube, and it makes a nice difference. I didn't try to apply the basalt wool, since it's loose enough that I think it'll just fall off without an outer casing to contain it. That'll change how it sounds again, but I'm currently happy that the truck's gonna be reasonably civilised at trundling speeds. (Hoping it's gonna be rowdy at a full-on Yomp, though.)
I did also manage to get the pressure limiting valve installed, and it's holding the supply to the brake servo at 6.5bar max, which I'm reasonably happy with. Whether it has the desired effect on brake sensitivity will take a test-drive to find out, though.
...speaking of pressures, while I was laying under the truck with my test-gauge measuring brake air feed pressure, I noticed the fuel pressure wibbles just a little. It appears to be only 2 or 3 psi, but is it anything to raise concern?
...by the by, that E-glass matting is the strangest sensation. It's like petting a very itchy dog.
