That's exactly how I do it. If I have to learn an entire evenings worth of blues/country/r&b/classic rock tunes, I'll check off the ones I already know, then go through the list with youtube and sort out the ones I could do right away. Then I grab lead sheets (chords/lyrics) for the rest and take a QUICK look at tabs for complicated/signature licks as needed. Rinse, repeat. I've done this many times between a Monday call and a Friday show. Must be working ok. I keep getting calls.