I've used the double uni-knot to join lines for a while now. All the directions I've seen show the standard 5 turns on the right, snug then 5 turns on the left, snug, tighten and trim. The directions show that on the right hand side you start the tag by looping it up and over the main line, do the 5 wraps and move to the left. Start that tag end Up and over the main line for 5 wraps.
If you tie this knot with something large like weed whacker line you can see that the 2 joins are at opposite angles. The knot on the right does a 45 falling from left to right and the know on the left falls from right to left.
Here's a link to example for how to tie the knot:
If you do the right hand side like most directions show but then do the left hand side different. Instead of going from front to back up and over, you go back to front up and over you end up with both knots at the same angle and they join up cleaner and make a slightly smaller knot.
Anybody tie this different than what the directions show? If so notice any problems with it? I used to break at the join a lot and now don't and I think it's by the way I tie the knot. Or maybe I just remember to put more spit on it that I used to.
Her'es 2 pics of double-uni-knots with 3 wraps/side. The first is per directions the 2nd is the other way.