In my opinion, go 1 imbue per fight
Depends on what ur doing farming/grindin...
If ur farming go 1 imbue
If ur grinding u should go 1 imbue as well because if ur forced to imbue twice in a battle then ur monsters are too strong for grinding or farming
Im lvl 43 in my other char(full itel sword/nuker(ice(cuz its kool and fire srt..)))
But in this one im a lvl 24 full str bowmen like u except i go fire becuase in the long run fire will be much more efective then light/cold
So i use fire and i use the first pacheon skill and combo pacheon skill both at 8 or 7 not sure cuz im keepin a 6 six defference i go first skill and the n shoot one,combo him,first skill again with 1 imbue so im lvl 24 gighten huyongo's and 1 imbue does it. For ur lvl i think ur going a small gap so my sugestion, if ur going with ice and full str bow, figh demon/devil horses ull murder them and they might get max 1 shot on u although ull have to use 2 imbues
To summerize try 1 imbue with fire/light but with ice its meant to be a 2 imbue cuz its slow but efficient (with double combo+ice imbue 95% chance u FB him(frostbite)).
COncluding

go with fire/ice imbue but in middle of battle dont switch imbues keep with ice if u start with ice or keep with fire if u start with fire