Sounds like you've got a decent plan there. I believe that the tutorial might be useful even if you are running Windows as long as you are using the Nokia Qt SDK. You should at least be able to compile the plugin and move this to ~/.config/mbarcode/plugins on your device to load it.

However, if you figure out your ways with QtWRT, I suppose you should choose whatever suits you best. In any case, good luck, and don't hesitate to ask if you have any further questions.