I'm looking at the pic above of your splice and it looks like you've got a trick up your sleeve for making the splice. I can't quite figure out what's-what. I see what looks like some additional pieces of wood, screws, and plastic. Could you tell me your technique here?
The additional wood is just scrap ply to stop my lead ingots from marking the panels.
The screws are to hold the ply down flat while applying the woodflour in the splice.
I set out one panel in place, screw it down to hold it in place and apply the splice. Then I lay its mirrored panel on top, with plastic or wax paper between to stop them sticking together and do the second one. This makes the panels identical to each other.
All the screws do is hold the panel flat to stop the woodflour from running underneath. With the second panel, I run the screws right through the first panels. Guarantees a flat even splice – every time. The small screw holes are easily filled and are a small price to pay for a perfect splice joint.