@revhed: I am afraid I do not understand your approach. Could you elaborate?
@evan: OK, the loop loop would be my intuitive approach (A1). Glad to hear the load capacity should be ok.
The ozone approach (A2) seems pretty elegant to me. The only challenge may be to find the exact correct location of the stopper knot in the single Frontline safety. Also I would need to integrate some kind of bungee in this single frontline safety to account for possible depower/trimming option.
A third approach (A3) would be to make both powerlines exactly symmetrical and attached to the depower/trimming option, hence making it easier to build. The safety would be a line that is fixed (about) halfway on one of the power lines. This has the advantage of no need for a stopper ball and no knot in the safety line so nothing can get tangled. I would just need to find a way to safely attach this line to the powerline.
Any suggestions which method is superior? Or is it a matter of personal preference and ability?
Edit: I attached a picture to hopefully make those three approaches better comprehensible..