Have been using my overlapping joint technique on my cruise ships - as had trouble getting the overlapped parts consistently cut cleanly.
Finally resolved this problem with the aid of a Dremel type device with a 3mm router bit and a small 3d printed fence part.
Joints not completely invisible - but fairly close.
Left hand side is printed with 0.6mm nozzle - showing the slightly rounded corners.
Right hand side is printed with a little 0.6mm square protruding and overlapping the joint at both sides, which is then shaved off to make a completely square corner.
2nd picture is of Dremel with 3d printed jig - then its just a matter of sliding the parts along and letting the router bit slice off the excess plastic.
