Always hated the after market solutions for Dyna saddlebags and detachable saddlebags. All of them kills the stock good looking turn signals. No adapter offered "good finish" from my perspective.
I never considered changing the turn-signals (like LED strips etc).
So, I bought a complete, mint condition, Deluxe (or switchback or touring) rear turnsignal and adapted it to my rear fender. (Yes, you must sacrifice 4 wholes on it, but if done correctly, can easily be covered with plastic hole covers.)
If I decide to not use the saddlebag in a particular day, I use Harley's bungee nut, hand tightened.
Let me know what you think.