Hmm, if I was in your shoes and had a choice, I'd take the light board. To me, sound can get a little complex (especially if you have mics, etc.) where the light board is sometimes (mostly, . . . hopefully) just pressing the go button.
I've also "called" a show where I operated both light and sound cues . . .so it's not like you are actually giving yourself standbys, you just press the button when you need to. The sound cues were pre-loaded into a computer and literally had a go button like any light board. Not a highlight of my career, but it was a paycheck.