34 degrees is cold but that's not what cracked your slab. Concrete makes its own heat while it sets, so a 12x20 pour in the 30s usually stays warm enough on its own for the first night. What got you was the gap between the pour and the outside air, plus that Flagstaff wind sucking the moisture right off the top. Spider cracking like a dropped windshield is almost always from the surface drying faster than the inside, not from the cold itself. A lot of guys will still pour down to 35 or so and just cover it with blankets and plastic the second they finish. Next time watch the wind and the sun as much as the thermometer.

Wait, are you sure the minimum is 1,000 pieces? I did fabric analysis on a Corinth assemblage a few years back and our lab only asked for 500 per ware group, not 1,000 total. Maybe your lab uses a different method, but I'd double check before you assume you're clear to run it. Also, nice work on the spreadsheet, six evenings of sorting shards is no joke on the eyes. Color coding is smart, I wish I'd done that before my bins turned into a mess.