As you have seen, to be able to form the second collar in this double collar Water Bowline shown in your
first picture, you had to pass the returning eye leg through one only of the two nipping loops ( the "upper" one). That does not affect its security, that is true, because the eye leg can never be secured while it is going straight upwards - but it does not improve the "look" of the knot either !
I would nt prefer that particular eyeknot from the Mirrored Bowline, or the Double Collar Bowline shown at (1).
At your
second and third pictures, you present bowline-like (post-eye-tiable) eyeknots that are based on the
slipped overhand knot, as their nipping structure. Very clever and original idea - a well known, much used, easy to tie nipping structure, that has tight spots within it, and can serve as a most stable "double crossing knot" s nub.
However, you go one step further, and you
twist the slipped bight . I do not believe that this is really needed : it makes the nipping structure too complex, more difficult to tie, without offering much. You have an already very convoluted, very tight nipping structure, I am sure you can find many ways to weave the collar structure within it, without having to add this additional / final twist.
See the attached picture for the first simple knot that crossed my mind, based upon this slipped overhand knot nipping structure you have thought of. The first round turn of the collar structure ( actually, a nipping loop ON the collar structure ), binds the lower parts of this complex "double crossing knot" together - and the tail passes in between the standing part s and the returning leg s first curves, where it can be squeezed and secured very efficiently. I am sure one can discover many more ways to do achieve the same thing : retain the integrity of the form of this "double crossing knot", and secure the tail into one of the more tightly squeezed points of it.
Now, in both of your shown knots, the paths of the returning eye legs to the collar tips remains almost straight - that is
not the best thing we can have ! It would be much better if this path of the continuation of the eye leg inside the knot s nub contains an L-shaped segment, a "step" that would help it to be "hanged" by the nipping structure, and a means to dissipate the flow of the tensile forces, before it arrives at the collar and at the tail - just as it happens at the "Eskimo" (-) bowlines. In short, your nipping structure is very complex, but your collar structure is almost naive compared to it - something that I do not hesitate to mention repeatedly over and over again when I see it, but without much success
( as one can see in the case of the dialogue about the Tresse bowline, published in another thread ).
1.
http://igkt.net/sm/index.php?topic=4306.msg26951#msg26951
