CRX
(CRX)
4
You’re thinking about doing something like this where I made a copper & aluminium plug.

If there’s extra space in the pill I usually fill most of it with more conducting material, aluminium or copper.
The copper squares aren’t the best for the job but give it a try. The first time I did these mods was with the squares soldered together then started using solid bar.
Depending on what driver you have, say thermally regulated drivers, it might be advantageous to have very close contact to the driver and filling what space is left with silicone cubes. Other drivers I would leave a slight a gap.
LED4Power sells ready made units for the S2.