Hey guys, wow this is an old thread!
Yeah, I made them on the vinyl plotter at the shop.
I had mine on the glass for a long time, but it eventually wore out so I took it off.
And yeah the holes are necessary for the light sensors, as was mentioned. You could use the one already applied to the screen protector too.
Whichever you want. I personally liked it on the glass because it felt and looked better IMO. I don't like screen protectors. The only problem of having it on the glass is that you'd have to apply it yourself and it's probable that you'll mess it up the first time or two. You have to be very careful applying it. You can PM me if you want one.
This is the technique I use though:
Thats me applying the palmguard to my MBP.