Thanks, that's really useful information. I was kinda guessing that's how it was going to be done, but after a quick test, it didn't work.
I seem to be replicating what you've done, but encounter the following problem...
It's setting the values of my Vector3 (e.g. world object at -6,1,0 becomes something like 220,200,12), I create a GUI object, but it's way off-screen. How do you translate the value to be screen relevant position like a 0.5,0.5,0 ?