I'd like to get for my kitchen (and, yes, for actual baking purposes). I wanted to go to a marble-granite crafter near me who advertises low-cost counter remnants, rather than buy a pastry slab via retail. This is something I'd leave on the kitchen island. Three basic questions: 1) what's the smallest size I should consider, in order for it to be practical for a variety of baking related applications, 2) are there any varieties i should either avoid OR ask for--types that are better or worse in terms of durability, porosity or any other issues; and, 3) how thick should it be? TIA.