I used the thinner version of the 2032 the CR2016 on my PT54 TR1200 builds on the tape and standard switch. On my green PT120 maglite was able to use no external power source and incorporated everything into the massive copper heat sink. All that was required for both was a mosfer and a bleed resistor.
BTW… Being a cheap bastard I buy all my lithium coin cells at the “Dollar Store”