Been watching this thread for a couple of days
It is my recollection that the bridles were left off the 2004 rules by error
aluminum poles will require bridles due the stress loads
I think Carbon poles would be fine with a D ring when running down wind in the higher wind conditions but I would have concerns as to the loading when beam reaching. Tapered poles which our rules do not allow for are can be built with D rings. I will check with a couple of the pole manufacturers and get there views on the D rings for carbon poles

Trigger ends were not allowed due to the fact they are not retrofitable to the old poles.

Just noticed this thread about bridles, and perhaps I can share some J-24 experiences. The class no longer requires bridles. This is possible PROVIDED THAT:
1. The twings will need to be moved forward, reducing the need for or load on a foreguy in the center of the pole
2. J-24 regattas rarely sail on reaches, all if not most is dead down wind.
I have taken the compromise way out, that is I have bridles on my pole that are duck taped such that the bridle cringle is essentially taped to the middle of the pole. If the loads get to the point where the pole is at risk, the tape rips, saving the pole from breaking.
Art
Nice Pear

I am in the process of reseaching the history on this and will have a ruling shortly

Charlie
Class measurer