I think Spock's adaptable enough to work with what he has and he may even 'help' some technology along with his future knowledge.
Although strictly, the phasers could easily have different power settings (courtesy of a little button somewhere) but you have to rotate the emitter to ensure it's on either 'stun' or 'kill'.
Plus, too many settings can be as much a joke as too few. I mean by the time of TNG a phaser was supposed to have something like 16 settings.
Which is kinda overkill.
'If the Apocalypse starts, beep me!' - Buffy Summers
'The sky's the limit.....' Jean-Luc Picard, 'All Good Things'
courtesy of Saquist