For the sake of neatness, you can taper and bury the tails of the double fisherman if you stick with hollow core. Obviously does not need a long bury but would still be better to taper. Can be done with other knots as well.
Use a throat whipping or stitch if you are worried about slippage.
Feedback:
After some Sessions I would Like to give a Feedback:
For the Rope Ends I went fit the "Waterknot"
Did Not Slip through at all!
For the middle Knot I Just made a normal one (I did Not want a Slider.)
Even if I am Not proud about it: but with too much beer and too much potato Chips on the Couch, I really Like the small Rope. Much more comfortable than my 8 cm wide Hook.