Before I found kiriba-ru I did the coin mod, there are some amazing coins out there that are a 100% match with the sizes you need.
UK 1p/penny is 20.3mm
EUR 1 cent is 16.25mm
that’s all you need, remove the top part/rim on the S2+ pill if you don’t want to use anything with 16mm.
Thanks but, I'm trying the coins soldered first and the if not I'll buy a 19mm plug used for plumbing either brass or copper, seen that done and seems to work! Will post about how it's going!
Euro 10cent is perfect, 19,8mm and solderes just fine will try that for now!
Yea the end caps used for plumbing like the ones i used on my BLF project they would also work and you can cut them to size.
They have copper ones also i think.
If you get pennies make sure to get old ones, there isn’t much copper in them now! I believe it’s pre 1992 they were copper, now they are just plated steel. Apparently when they stopped them they were worth 1.5p in copper………if only we knew lol!
Yeah coins dien't work lol, just tried haha, not sticking to eachother! So I think plumbing it is lol!
They do stick, but you’ll need more heat.
coin - solder paste - coin - paste - coin, etc
then hit it with a blow torch in your vise
Yeah I just have a small mini torch but surely that would do, maybe sand smoothbis needed first?
Well, I just went through our coin collection (saving up for years - 1p 2p 5p in a bottle) had 760g of pure copper coins, 1p and 2p. Easily done with a magnet 
Well just got rhe coins soldered together!
A lot of heat and cleaning with acetone first did the trick!
Would you mind posting a few pictures while you are going along with the mod?
The other day I was thinking about going the same route with my S2+.
+1 here 
Although I have a pill and a spacer from kiriba-ru (hence my post above) I will probably need a 3rd spacer but I’m having difficulties to get a “proper” pre-made material. So maybe this method can help a bit!
How many MM thick is the spacer?
Edit this would depend on the optics being used.
regular s2+ spacer is 6mm thick.
I tried to make it with 2 coins first which is 4,5mm kd triple with included optic! Seems like there is no 'play" space seems nice and tight! lol! 3 coins is roughly 6mm fits fine still! Should I use the 6mm eventho 4,5mm works too?
For pilled flashlights you can make spacers not so precision because you can compensate wrong height just by screwing/unscrewing pill.
I made different heights with coins depending on the light I wanted to put this in. protected vs. unprotected battery.
One S2+ has 8+mm spacer for shorter, really tight batteries. Another only 5mm because I sanded away a bit too much.
Also depends on the springs you are using, which driver, what tail cap, etc
I used 10 cent euro coins!
Ok pics coming soon, too tired now for that lol!
Anyways 3 coins is needed for proper fit! I sanded them smooth and solder them together aswell as solder the top of the pill, where it's about 1mm recessed, flush and sanded it smooth! Now the top of the pill is smooth like a hotplate!
I have done two spacers with coins and it all went well, but then I thankfully found kiriba-ru and his selection!
While making coin spacers is a ton of fun (“I did it on my own”) - you would also have to account for sanding time, soldering, drilling the whole thing and then cleaning. All in all, it is fun to do and a great workout but an actual copper spacer for a few dollars is probably the more economic solution.
Coins however also allow to alter the size of the coin and make different spacers easily - you could combine 16, 20, 15, 20 (and so on) and it looks like more like a heatsink rather than a spacer.