tru tru. Tank 09 does ~150 Fenix lumens on 10440, and ~90 Fenix lumens on NiMH. That's very bright on NiMH and not too bright on 10440.
but it is safe to use 10440 on the E09; you can enjoy longer runtimes, and current draw is low/safe too. i measured currents meticulously and noted them in the table
anyway, i don't use my E09 nor my ES12 in practice anymore. they're too nice, too likable, so i want to keep them in mint. I prefer to RL-use lights where i don't mind scratches, drops, failure up to death hh.