I actually wouldn't use a paper wallet. I'd get a small USB stick and create a text file. Then add the private keys to the text file and put the text file on the USB stick.
Throw the USB stick in the safest place you can imagine and you've got yourself secure holding.
I guess this is a good practice since USB is one of the most portable devices that we can have. Then we can also duplicate those copies on multiple USBs. We just need to store it in the safest place that we can remember. If we forgot it and if anyone can steal it then it is not safe anymore. There are safe that are double-locked, digital or manual, as long as it serves its purpose to keep the wallets safe.