Yes, interesting attempt.
As for syntax, it seems that traditionally Indo-Europeanists are not very inclined to guess about it or attempt a reconstruction. I'm not saying it's a bad idea to try though, especially just as an exercise.
On the other hand, the reason for using the Lord's Prayer is because it already exists in so many languages because it (or more of the bible) has already been translated for other reasons. So reconstructing it sort of goes against that although it helps to then compare to the other languages, so there's nothing wrong with it in that sense. Something else to consider is the universal declaration of human rights, which is preferred by some when it is available in a language. Of course who knows whether that would be culturally coherent in this case!