I like the sub-C cell adapter I made at one time: https://fuckcombustion.com/threads/the-magic-flight-box.750/page-1078#post-1450090
This preserves the 'feel' of using the box.
I now clean my CCDs in vinegar/water. Works wonders. The SS CCDs are not that brittle. I have lost maybe 2 in all my vaping time with DV. One got stained with something and another was lost. But non had become unusable.
I haven't tried the silicon o-rings on the DV. I like the toughness of the FKM/Viton. For thermal consideration, yes, silicon is king.
I wonder if a rolled silicon o-ring would split wooden or glass stems.
Look for a Canadian o-ring distributor. You are looking for "FKM" (Viton) and 1x6 (1mm profile diameter ands 6mm ID).
You might want to chase that burr though. I've lost 1 o-ring in 5 years.