This is not what your doing exactly, but may give you an idea of what you might do.
I have a rocket on rails I made to pull a Lionel Marvin the Martian Earth Disintegrator, Acme Instant Martians cars, and a few bashed for the cause. I used a modified hotbox car smoke unit, and flashing purple LEDs to accent the smoke coming out from the rockets nozzle. I used a diode & switch for half, or full smoke. This it at the end at about 1/3 output. If you look you can still see the "flame" jump a long way 4"+. Full power is kind of silly(and think of who's saying it
). You cant see anything! It fogs over the table in no time. But it is likely I will do it soon for the kids.
A red micro LED chip centered in the inlet supported only by its legs? Opening Sm.unit ports to increase flow might help to offset the blockage.
Or If a "pipe" exhaust can be used, a clear plastic/glass one would allow light in from outside of the tube(led next to it) without any interference into the smoke space. I would bet on a bright, but soft glowing led -vs- a beam. Dig deep into specs for projection angles! They will make a difference.
