The old RRT01 also legos with a Convoy S2 tube, IIRC. But it requires sanding down the tube threads to make it short enough for a good fit. Or dealing with exposed threads and no waterproofing.
Now let’s find where to buy and old RRT01 
and here is a replacement reflector for the Original RRT-01
following info courtesy of Coppet:
a replacement lens that also fits 2019 RRT-01
and a black clip option that also fits 2019 RRT-01
Lol 138 bucks for an outdated product
Sounds better when you convert to USD. Don’t you feel sorry for us Aussies 
Oh, those are AUD ? sorry I didn’t see it 
ANyway, that’s still more or less the price for the 2019 version 
But most of us do prefer the old model.
I like the looks of the new model, the old model looks somewhat boring (except the Ti model, but then: the new model in Ti would look even better )
I find the new model to bulky for EDC and almost double the weight.
I agree 
Yeah I agree with what you said about aesthetic…
That said, I got the 2019 for a review, so basically for free (is free time that free ?) so I’m not considering paying for an older model 
I totally impulse bought these without reading “original” RRT01. Any chance you ran across some drop ins for the new model?
I never tried any in the new model. The reflector in it seemed decent. Its possible this same reflector may drop in the new model. I measured it at 18mm earlier in this thread.
unmodified optic
legs wont fit into the Original RRT-01
trimmed leg sides on non-carclo triple optic for RRT-01
the non-carclo brand narrow clear optic sold by kaidomain is modified to fit without any glass lens over the optic, because the optic has a smooth face
when using a carclo 10507 besides trimming the sides of the legs as pictured, it is necessary to install a glass lens over the optic, to cover the holes on the non smooth face of the carclo narrow clear optic.
Just how hard is it to open the head? I haven't tried real persuasion yet (my strap wrench must hate me by now) but I haven't budged it either.
I've got an original RRT-01, which I much prefer the aesthetics of.
Lots of tape and vice grips an finally a pipe wrench for me 
Turned out OK though
Soft wood jaws in my vise, and a leather belt plus big pliers
Thanks for the responses. I'll add this one to my list for whenever I next have time
Interesting, it seems that the external part of the 3 reflectors was also trimmed :
