Rough lines of spotlight beams in fog

hi, I am relatively new to all this so apologies if I’m missing something simple. I’m trying to emulate concert lighting, ultimately I don’t want any fog to be seen other than from the spotlight beams onstage. I have created some simple local fog and am using the DMX Moving Head fixture.

I would like to have smooth lines at edges of beams.

And also the light can be seen through the housing of the Moving head itself.