Now, the tails of the Dragon 2 and Dragon 3 are driven through a path where, at their last passage through the knot s nub, they are nipped more effectively than the tail of the Dragon 1. However, they are nipped twice, at the same point , by the same strand ( the continuation of the standing end). This is not so good, as, at this one point, the squeezing force on each segment of the tail is divided by two.. I think that you can utilize the "8"shaped nipping structure more effectively, if the tail is not only nipped twice, but also nipped at two different points of this structure, by two different segments of it.
At the Dragon 4, the path is different, and this idea of the tail going over-under-over-under four parallel strands, is very interesting, indeed. However, I think that the last segment of the tail is not squeezed as hard as it should, at this last line of defence.
The Dragon 5 is perhaps the best of all the other variations. I have tried a slightly different version of it (See the attached pictures), because I want the tail to fit into the last bight even more tightly. I think that it is a secure bowline-like loop, that deserves further evaluation.
( I like the single, solid braided nylon (?) rope you use, but I would prefer it a little thicker, so it takes smoother curves for the pictures.( 1/2 inch , 12.5 mm, would be better, I believe )