Cheats/tips...Success!
I was able to get Drive Setup on the Centris, it found, and then formatted the drive to HFS and I think I'm good to go...
I'm going to proceed to get OS 7.5.5 on the new drive, then wipe and remove the old drive.
Since the drive is bare, you can partition it in a little more than a trice (use Drive Setup again). You could begin by creating one partition that is just under 2Megs, and another that occupies the remainder of the 4G.
You could then drag the icon for your 80M onto the icon for the larger partition in your new drive and, once the ensuing copy operation completes, dig inside that partition and pull the contents - minus the Desktop Folder and possibly Trash - out of the folder named for the original drive, and drop it into the root of the new drive...
You'd then have successfully cloned the 80, and could then boot to that partition. Open the Desktop Folder one level down, zoom the window for it, and you can probably figure out what's going on there...
You can keep the 80 around until you're happy with everything - then toss it, or use it for your virtual memory, if any.
Still later, if you find and install a copy of System Picker (or is it Switcher), you could copy the contents of the Network Access disk onto the 2M partition - along with Disk First Aid or whatever you like - to have an alternate boot partition (assuming just the one drive), to which you could boot in order to fix the main partition...
Creating a second boot drive or partition is soooo much easier on a Mac, and so handy.