IMHO, because the flat has less marbeling, it shoud go above the point. I dont see any harm in cutting them in half. Put them in early in the morning, as briskets have a tendency to plateau like a pork butt. You might want to also foil them at about 170 degrees, so they steam, Once they hit about 190, you're there. If you're using your verticle smoker, put them on the two racks in the middle of the smoker. Some people like to take them out of the foil and continue cooking for a little while to set the bark. Hope this helps. Let us know how it comes out.