I was recently in a very similar situation of trying to figure all this out. First, what amp head are you using? Wattage and ohm load are factors that may exclude some cabs (ex: using 500w amp at 8ohm into a can rated at 200w at 8ohm is not advised). Others here have far more experience than I do. So in addition to factoring in weight consideration and size of venue, it helps to know what you'll use to drive those cabs and in what situation you will be playing.
my personal preference is to start with a single 15 but most here might disagree, it's pretty subjective. With two cabs my favorite combo is a 115 and 212, others swear by 2 212s or 810s, etc.
my personal preference is to start with a single 15 but most here might disagree, it's pretty subjective. With two cabs my favorite combo is a 115 and 212, others swear by 2 212s or 810s, etc.