We really like the look of butcher block countertops. The easiest way to get them was to buy from Ikea. I had to cut a few inches off the back but it was a perfect length. I used the sink as a template for the cutout and subtracted 1/2" from that. I drilled holes for the sink bolts but found out later they weren't long enough to put the nuts on under the countertop. I haven't found a solution yet so the sink is just siliconed in.
I used the sink as a a template and measured .5" from the outside edge and marked a cut line with the square. I tried to leave as much surface to support the sink as possible.