Well: no way experienced (in my film setup I used a single strobe) But this is how my current brand-second hand-new looks like.
I struggled with it as well, and this is my design...
From the housing, I loop the cord around the bottom screw. I use the coiled cord to keep it a bit tight.
The box hangs a bit, but it is very sturdy, I would be more worried about the cords going into them. Thats why i used some electric tape to stifen the joints.
I dit one dive it, no problems ( I only used the wrong lens for the situation... not really a wide angle buff yet, and the conditions were not good enough for it to be easy....