Essentially you are creating a paper wallet.
Make sure you use an Air Gapped PC.
Why not just use a paper wallet generator?
as I understand, paper wallet generators are js scripts that run in a browser- I would not trust that...
at least, you would have to save the html with the js locally, disconnect rom the netwook while you use it, and scrub the browser thoroughly afterwards.
to me, that makes the old fashioned dumpprivkey method much easier and less insecure.
As I said, Air Gapped PC... probably best is to use a LIVE CD type install so once you turn off the PC, everything you did is gone.
I'm not sure why you would trust a QT wallet any more than an HTML wallet generator. In each case, you want to make sure you are offline. in other words don't trust either one to not share your private keys. I would still do it on a LIVE CD air gapped PC.
The advantage to a paper wallet generator is that it will allow you to encrypt your PK. It will provide you a QR code with your keys and it will generate a PDF of said information to allow for you to easily print several copies to "backup" in various locations. This is much more error proof the manually writing a private key down.
Up to you of course.
