with regulated mods, you don't need to take amps drawn into consideration; the mod does that for you....it's not as simple as x watts equals y amps as it is with a mech mod.
Actually you have it exactly backwards. It's the
resistance that doesn't factor into battery safety with regulated devices. Also, on those devices that show an "amps" value on the display, that figure is the (meaningless)
output amps delivered to the atomizer and
not the (useful to know) input amps being drawn from the battery/ies which could lead to your confusion as
that particular amps value does
not need to be taken into consideration.
...but it very much
is as simple as "x watts equals y amps," at least assuming constant battery voltage (and you should assume low-voltage cutoff of 3.0v (per battery) under load, for safety calculations, unless you know the actual cutoff point and power efficiency of the device in question.) For reference, "y" = "x/3" so 60 (x=60) watts, at 3.0v cutoff, equals 20 (y= 60/3) amps. Multi-battery setups increase this wattage "speed limit," either by doubling/tripling the battery voltage (wired in series) or by "sharing" the amp load between each cell (wired in parallel); the calculations are different but the end result is the same: stay under 60 watts, per battery -- or (amp rating x cutoff volts) if you're not using 20A batteries, or a device that cuts off at other than 3.0 volts -- and you'll be fine.