Tried this tool -
http://brainwalletx.github.io/ chains tab, armory and put in the 18 4 char alphas in the paper backup text box. This generates addresses but none of them have anything in them (at least not the first 20 and the tool seems to be limited to generating the first 100)
If you enter the root key correctly, it should generate the correct addresses.
If you don't see any fund in the generated addresses, either you entered a wrong root key or the wallet has never received any fund.
If I can find a secure windows or linux machine to use, what version of Armory should I try?
You should always use the latest version of Armory.