What are my options

I have ordered one of the Sofirn C01 lights, that has provision in the tailcap for a 3x5mm magnet and a 1.5x6mm tritium vial. What does one use to fasten things like this to the light? I really don't want to spend $20 or more to buy some UV potting compound and a UV light to set it just to set these things in a $7 light. Will a silicon based adhesive work?

I use an epoxy called E3000 available at craft stores and probably box stores. It's a super grippy glue that remains a wee bit flexible so it can adjust to changing temperatures (and associate physical changes of items bonded together).

I viewed 1 ml tube of Norland on eB, but still cost more than that light, heck the trit vials are more valuable!

..Go with Mr Bykfixers recommendation👌

A consideration when deciding to use superglue, epoxy, Norland, etc: trits do wear out, maybe 6 years, maybe 10 years. It can be challenging to remove the trot to replace it. I don't worry about it in my Copper or Bronze lights because my dremel does a nice job. On anodized lights, I use some of my woodcarving tools. I mainly use Norland, but I have probably 30-40 lights with trits. I have one friend that just uses a tiny amount of clear nail polish & swears it works great. I have also use the 30 second cryanoacrylic super glue that remains flexible for 30 seconds -I will be checking out bykfixers suggestion as he has a great track record and I find his suggestions to be really right on...

My first thought was the cheap super glue like sold at Dollar Store, yes for $1. But to be honest I'd bet ($.01) that the C01 dies before Trits goes south

I luv, luv, luv some super glue....
Until the day it fails unexpectedly.

Nothing like raising a coffee cup full of hot brew to your lips and the super-glue'd broken handle lets go after a year.
Ouch, lap fulla hot coffee aint my idea of fun at 6:30am. lol.

About twice a year my pop would say "can you reglue the nose piece on my glasses again?" Yup, sure thing dad.

Tried E3000 and he didn't have to ask anymore. Want it gone? Fingernail polish remover does the trick.

I superglued my chest/knee/finger back together after various accidents and they grew back. I like superglue!