I have an RS so I speak from experience. You must have an ABSOLUTELY square clean edge to start, period. By square I mean your lead edge must be 90 degrees to either the right or left side. The lead edge must also be dead flat, period.
Here is what you do.
1) Make sure you have a perfectly square leading edge.
2) Put 2 layers of 2 inch masking tape on the top edge, square with the leading edge.
3) Out on layer of 2 inch masking tape on back side of leading edge.
*Why masking tape? Laminate doesn't stick to masking tape. This little trick allows you to keep resetting until you get it perfect. It also makes the edge lay dead flat.
4) Feed in just enough of the print so it stays put.
5) Carefully measure from rear edge of tape to a point on the platen to make sure it is feeding even.
6) Punch the go button.
7) Happy happy happy!
This is the same method I use for long runs. We have done 60+ feet rolls like this with only a quarter inch drift. My infeed is dead simple too. I'd tell you about it but it's embarrassing.