Here is a video.
I bought some junk yard head lights to practice with. They have this hard sealant around the lenses. I only separated one of the junkyard light assemblies. It has the hard dark gray sealant on it and it was a bitch took 3 hours of heating prying and pulling. The headlights in my car have the black buytle rubber sealant on it. I think the head lights with the black bytle rubber stuff would be easier to separate as you can easily pull it away with your fingernail.
I contacted a few places that install this stuff. One place will not do it if the headlight has that hard gray stuff on it.
I was thinking about just sending my lights in to ORACLE to have them do everything. Halos, paint my bezels and all. It will cost $500 for everything and it has a lifetime warranty.