From a tonal perspective, the back and sides might not be the best place to start. The construction (size, shape, bracing pattern, etc.) will exert the most influence on a guitar's volume and tone, at least in my experience. So if you're going with a Taylor, you'd want to start with body style (GA, GC, GS, etc.). The next big influencer in my experience would be the top wood. Whether it's spruce, cedar, redwood or a different hardwood like mahogany or koa will depend upon what you like to hear. From there, it will become easier to pick and back/sides wood to facilitate your "flavor" preference.
What's your playing style? Do you strum, pick or use finger style? Will you use the guitar as vocal accompaniment or will you play without vocals? Will you play solo or in a band setting? Do you like a deep throaty sound, or a glass-smooth liquid sound with sparkle or an earthy, woody sound? Answers to all these questions will help guide your BTO choices. Please share with us so we can better advise you, but most of all, have fun in your quest for your next guitar!