Virtual Mat Numeric Markings - NEWBIE

[Mags B]

I just 'graduated' from a Cricut Cake machine to the Silver Bullet. I have never used software like SCAL before. I've watched ton of videos but I haven't seen anything that covers this. The 0,0 orient point on the Silver Bullet cutting mat is in the bottom right corner. The 0,0 point on the SCAL Virtual Mat is in the top left corner. I have to place the material between the rollers so can't line up at the corner. Is there a way to change the orient point on the SCAL Virtual Mat?
Also, is there an eraser to remove large portions of a image? I've had quite a few issues where deleting nodes really screws up the image's shape.
Thanks,
Mags