Forget using rulers. My Graphtec doesn't even have rulers and it feeds straight. What I do, is make sure the pinch rollers are the same distance, from the edge of the vinyl. When I get real picky, I use a tape measure and measure like 1 1/4" from each wheel to edge of vinyl. I don't know how many pinch rollers your cutter has, but my 30" Graphtec only has 2 and feeds perfect. My cutter has a prefeed option on it. And I always prefeed the vinyl for long cuts. It actually puts the roller marks in the vinyl, so that the cutter follows those marks when I cut my design. Those pinch roller marks don't hurt a thing. Always prefeed the entire length of the order and have the vinyl laying to the back of the machine, never pulling on the roll while cutting. Make sure the vinyl roll is straight on the cutter and behind the cutter. I put my hand inside the roll and make sure it is tight under the pinch rollers, You can see if the vinyl is even across. If yours does not have a prefeed option then use the arrows of your machine to prefeed the vinyl back and forth.