You're drawing sweet-f-a current, so what about using an already protected 18650 cell (or two) instead of your raw lipo.
The metal shell of the 18650 will give some extra physical protection (consider than handheld tools will be dropped, stood on, potentially driven over....), are easier for Joe Bloggs to handle (if you want to be able to swap batteries), and you can get them with protection circuits built in (a small protection circuit PCB Is usually heat-shrunk on top of the negative terminal, makes the battery a fraction longer)).
You can also get 18650 holders with the protection circuit in the holder, made for taking unprotected 18650's, but I'd recommend using protected batteries rather than protected holders.
Whatever the case, you should of course properly test your protection, don't just rely on what the chinese seller says, make sure it works.