I can't speak to all of your concerns or an alternate method but it was pretty simple to add the TWO hacks necessary to alter the screensaver images.
I was prompted to do it because I engaged the Password Protection function on my K3 and want MY OWNER info displayed when the unit went to sleep and displayed the screensaver. In order to display that info I needed to install my own edited images (or even the default but edited) with my Owner info. So I went for the hack. It was very easy.
From reading about it in the subforum, it does not sound like there should be any repercussions from installing the hacks.