Safest way to use a mech and build coils, is to know your vape chit first. Have a thorough understanding of Ohm's law, know the amp capabilities of your batts, and be able to build coils consistently and competently.
Yes, must look at the amp requirements of your build, making sure the batt has enough amps to supply the demand, and when a short happens, things get hot, really fast, like the switch, mod, batt, time to disassemble quickly, lay the batt out on the dirt and get back Jack, or something like that.
Building and mechs are not for the entry level vaper, seriously. Before one can build low at a competent level, one should learn to build at over one ohm first, like 1.5-2 ohms. Once one can consistently hit the target ohms, and have a competent coil that is wicked correctly, then one is ready to cross rice paper with out leaving a trace, or something like that

Vape long and Prosper.!!!!!