I have some wide items I need to engrave so I bought the F1 and the slide extension. I'm very impressed with both of them so far.

The items are as wide or slightly wider than the extension, and the engraving needs to centered horizontally and vertically on the material. I lined up one item against the ruler on the slide extension, but the item engraved about 20 mm to the left of where I thought it would engrave. Where should I have put the material on the left edge, and is there a better way of finding the exact center of the material so I can match it with the artwork? For instance, with the D1 Pro you can line up the exact relative center of the laser over the center of the material.

Thanks!