For your offline wallet on dedicated computer:
Why does it help to be offline STARTING before installing Linux? I thought it only matters that it is offline forever-- STARTING right before the wallet is created.
But many guides recommend to install xubuntu offline with apt-offline, etc.. That is a PITA. Please explain the benefit.

It's so much easier to install the OS and armory/electrum while online, THEN unplug the ethernet cable and superglue the port

Can you refer me to a complete guide? So many are different/outdated.
Thanks again, sorry if redundant.
If you are replying to me, I don't think I ever said to be offline before installing Linux. Of course you need to get Linux from somewhere and that is probably the Internet. I agree that you should install the OS and wallet first, then disable the Internet.
I don't know of a complete guide. You want to first create the Linux LiveUSB. How you do that depends on whether you are currently running Linux or Windows. The following is a guide for if you are running Linux.