24" bars would be fine. I'd honestly start with one and see what you think. You're only asking for a 12" spread. Easily doable. If you go two, there definitely would be no shadowing. But keep in mind they aren't controllable in intensity and you'll need to run a timer to turn them on and off. Still an excellent option.So I see they have 2 foot and 3 foot, would the 2 foot bars be ok at appropriate mount height? For this price could easily get two bars to start also.