As a few of you know I have a V6 in a hot rodded 48 Vauxhall .When I modified the wiring harness 5 years ago it took me the best part of a week and I found the most difficult part was joining the many wires without making a large lump in the harness. The best way I found was to stagger the joins and shrink tube each individual wire . When twisting the wires together before soldering they can create a rather ugly lump or come untwisted in the middle of the solering process. Its like you need one more hand to steady the wire while the solder cools. So this morning when getting dressed I came up with a great solution .
Not the most complicated of jigs but it works well