G'day Ian,
The arrangement that I have circled in this snip from your attached .pdf will not yield a fully closed box which I am assuming is your intention.
I have also assumed that the etched lines are fold lines and will be folded towards the etch lines. If that is correct, the folds will produce an edge-to-edge alignment, rather than a butt joint.
In similar circumstances, I have used the drafting arrangement in this snip from one of my own etch tools.
This was done in Autocad, and our drafting conventions are a bit different. The red image is of the etch tool for the front side of the etch, and the blue image is for the reverse side of the etch. Hatched areas common to the mirrored drawings are through-etched, equivalent to the white lines on your mirrored artwork. I have circled the notch that will allow the side panels to cover the edge of the base to form the butt joint for soldering.
In your drawing, that will have the effect of widening the bottom edges of two opposing sides by the material thickness, and widening the three free edges of the lid also by the material thickness. Gosh, trying to turn the visualisation of this into a sensible English sentence is being problematic!!
I hope this might prove helpful.
Regards,
Gavin