On SolarForce L2 can be fitted perfectly a photo adapter ring 30,5 mm. In this way it is possible to combine different filters and lens.
I added a wide lens 0.5X, but what happens with a tele 2.0X?
With an XM-L + wide spill is only a little bigger. With R2 + tele should be more thrower, But I think the best thing is to use it to add filters at low cost.
If we are talking about colored filters, I would stick with the lens replacements offered by SF.
If you need more colors, you can use colored gels used for photography, just cut them in the right size and shape.
These gels are available as a commercial samples from time to time, this is the way I got my free set of gels.
But these lenses are made to collect light from the big end, and converge all the light into the small end (for the camera to see). If you emit light through the small end would the lens only serve to make the flood bigger? I only have a basic understanding, but I don’t see how attaching a lens would make it throw more, only flood more. I may be wrong though, of course; because that’s just my take on it.
And also it would cut lumen output by like 5 times anyway, because the small hole where light passes through is so small (made for a camera sensor).