I read a thread about the gap at the bottom of the headlight trim ring when adding a new trim ring, I had the same problems with the gap at the bottom on my 09 ultra, here's how I fixed it,,,
first I removed the stock trim ring, then there is an inner metal ring, I used a pair of pliers to slightly bend the edge of this ring outward for a little extra grip, ( you'll see where to bend it),,then I took the inside of the new headlight trim ring and lined it with sticky back foam (sticky side to the trim ring) it is the same foam used to put on a truck cap, just cut it to fit, one layer should do it,,,now install the ring and do not use the stock ring,,,mine has been on there for 4 years now and has not moved yet,, and no gap,,,

 

That's what I did. Works like a champ!

 

I did the same thing. I had a fellow rider ask me at bike night on how I got the ring to fit so well. I explained it to him and the following week I seen him at bike night. He got it to fit perfectly. He was happy with the way it turned out he bought me a beer.