I'm guessing you're talking about the "old style" L1 and KL1 heads. Both have a hex nut at the base. The old KL1 had four ribs along its length. Both used an optic (NX05?) which gave more of a flood pattern than the new optic in the new heads. The new heads have a relatively tight beam which seem to be optimized for throw.
The best advice I ever read was to fill a small pan with water. Put it on the stove, and bring it to a boil. Dunk the head in bezel first, just up to the edge of the bezel ring. Leave it there for about thirty seconds, then pull it out and try to twist off the bezel ring with a rubber glove. I found it helpful to try to quickly dry the head before twisting. Be careful not to get burned. I'm not sure if this works because the heat breaks down the black loctite, or if it's simply because the bezel ring expands from the heat. The expansion might be enough to give you enough play to get the ring off. If you leave it in too long, maybe the whole head heats up and it doesn't work? I dunno...
After you break the loctite, you can usually loosen and tighten the bezel ring at will. Loosen the ring and tap the sides of the light to re-position the optic. Tighten the ring back up. The optic will almost certainly shift while tightening. See if you got it aligned correctly. Repeat ad nauseum. Be careful about repeatedly tightening up the bezel ring. I'm not sure if you're applying undue stress to the Lux emitter. I think the back end of the optic may be supported by the emitter, and I don't know if it's a good idea to keep applying force to it. You might be better off just replacing the optic with a McR-18 reflector, or keep the stock optic but use some kind of diffuser.
None of this applies to the "new style" L1 and KL1. I thought they typically came with fairly good alignment, but maybe I'm wrong. Good luck!