Nice video Dave.
Could you have used an isolated coax instead of bare metal, a tab of RTV silicone at the connection and done away with the plastic coating?
Sure, but I didn't see those pre-terminated. I'm sure there are ones, so buy those if availabe.
I should have just slipped over some heatshink before soldering, but I had the can of stuff and thought that might be cool.
I relate to the shorting out the circuit you are testing but at the other end would it might be a good idea use a DC blocking connector to you spectrum analyser, just in case the probe touches something even though you are protected by the outer shield? I know my HP8561E has a 0 DC MAX warning at the input connector or can you trust the coupling cap in the amp for that?
Sure you can trust the coupling cap in the amp, that's what it's for.