You'll get different answers, but personally I'd keep a steady pace. I'd rather run in the heat having more left in the tank for it.
So far the comments have mostly been about terrain and hills. With the summer heat a factor and the course being flat, would you suggest starting faster while the temps are the coolest or still try to keep a relatively steady pace? I expect high 70s at the start and near 90F at the finish. It's a 6-hour race and I'm a 5:30 marathoner.
One theme stuck out from WS100 this year - heat management. The leaders were laying down in streams, soaking shirts and hats in ice, and drinking plenty of cold water. I think Bhearn's advice is right on. If you go hard hoping to get in as many miles as you can before it gets hard, chances are you will pay for it later, probably with a DNF.