What we’re doing in those tutorials might look kind of complex, but it’s actually a fairly easy process.
Step one is to split the design into sections less than ten inches tall. You’ll want to do that because you want to work with shorter segments. (it’s a time saver for engraving and if there is any misalignment, the effect is magnified on longer stretches.)
Step two is to add some indexing marks out to the side. That creates a bridge between the design parts and the printed results.
Step three is to use your eyes in the bed of the machine, not the image on the screen, to match up the indexing marks as you print them, and when you shift the material up. If you keep the material perfectly level against the side of the tray, and do not let the jig shift, that creates a three-point matching system that does a pretty good job of aligning things.
We actually do something fairly similar with the Snapmarks, so understanding that might help…there’s another writeup at the end of these notes on using the Snapmarks for Passthrough alignment: (Those come out perfect. But we still have to split the file before printing it.) 