Thom, I have hunted pronghorns using every possible strategy in Colorado and Wyoming. I have been outfoxed and just plain beaten more times than I would like to admit. A waterhole setup works much better than any other strategy; your plan B, and plan C sould be other water holes. I hunt a place on public land in Wyoming with two available water holes. I camp and leave my vehicle parked on one and walk to the other (about 2 miles) to hunt. That strategy ups my odds.
Now, water hole blinds. Ideally, you want to have as little sticking above the ground as possible, and build it a few days before you hunt. The best setup is a pit, let's say 18"-24" deep-deep enough to fashion a dirt seat either on the rim or slightly below ground level. Erect a dome roof from weldwire over it and thatch it with local material. Leave big enough window(s) to shoot through. Make it big enough to move around and cant your bow. The most important part of this design is the roof over your head, which puts you are in the dark where you can't easliy be seen when you move, and it's cooler on those hot days! Wind is as important as with deer and elk-I have had Pronghorns come into a waterhole setup from directly down wind. But don't get seen, hence the purpose for reducing your profile, using a roof, and staying in the dark.