P60 Quad build battery/spacer question

Hi there, I have been using 2 18350’s in my kdlightker P60 for a bit but today built a quad with parts sourced from mountain. The flat top 18650’s I have in my other lights don’t seem to be long enough and I think the 2x18350’s would exceed the 4V driver limit. Should I get a “protected” 18650? Are they a little longer?
Thanks for your input!
Pics

2x18350 should be the same length as 18650.

BUT i believe your driver in these P60’s is for single cell only which means you can go freely with 18650.

If you could post some info about the driver that would be great.

Thanks for the confirmation, it’s the MTN electronics 17mm FFet with GuppyDrv dual ML.
I swapped out the tail clickey and the longer spring made the difference…

Oh yes, single cell only!

IF done right this one can burn pocket.