Howbow a ’502 or similar drop-in?

At least in theory you can get one of these:

https://www.illumn.com/ahorton-27-2mm-aspheric-glass-lens.html

with the spacer and tweak it to as much/little as you want it focused (how far you screw down the spacer onto the pill, replacing the reflector of course).

I say “in theory” because it’s not so great from personal experience, as both lenses I got have a flattening or “bellybutton” at the top which distorts the beam. With a good lens, though…

And a ’502 (or similar) should fit fine on Picadilly rails.