**P60 design**

I should say the triples would be great with the copper shell, I just think that a nonDTP quad mcpcb wouldn’t be able to take full advantage of a copper shell and would be better matched to a decent aluminum one.

Sandalian might have a point. When you look at the Sportac dropin’s
you can see that the rearside of de dropin for Surefire (SF) differs from the dropin for (generic) 18650 hosts.

You can use an adapter ring http://www.nkon.nl/eagletac-flashlights/adapter-ring-for-surefire-dropins.html

Just my 2c.