I live here in southwest Wyoming, and pretty much everything stated is accurate. I use a .260 AI, which runs on par with your 6.5x284, I'm sending 140 VLD's at 3070 fps, and I'm excited for the 156 to come out, as that should help the wind bucking even better.
I have killed somewhere in the neighborhood of 15-20 pronghorn, and have taken friends and family out on two or three times that many sucessful hunts, every year I get 2 doe tags and if I'm lucky score a buck tag. The 140 VLD does very well, but last year my cousin used a 180 VLD out of his 7mm rem mag, and it performed identicle. It's all open and flat, so judging wind can be easier than in the mountains, most of the time a kestrel will give you accurate wind readings all the way out, assuming your in the same terrain the goat is in, as in your not shooting from a covered patch of willows out to open plains. Still, make sure your wind judgeung is honed up.
Try to go out early, not because the goats are more active, if your in a decent area it should be more like pronghorn shopping instead of hunting, but because the wind usually hasn't picked up yet. My average pronghorn shot is around 500ish, ranging out to 876 as my farthest.
Also, the cooler morning is better for the meat. Out of the 30+ pronghorn I have eaten, the best ones are the ones that are cleaned out the quickest. We have gone as far as to hang them in a rack in the back of the truck, skin them, wrap them in a sheet and ice them in the field to cool them fast. Try not to shoot a goat that has been running like crazy either. When a spooked goat runs, it goes alot farther than a deer. Also, if you can get them near an alfalfa field where they are feeding, the meat is usually better than brush goats. DO NOT AGE THE MEAT. They are not a deer. They will only get more gamey. So be prepared to butcher and cool the meat within a day of taking your goat. These are a few things I have learned in 20ish years of hunting pronghorn. When people say they don't taste good, it's because they either overcooked it (a detriment to all wild game imo) they didn't take care of the meat properly, they gut shot it, or it had just ran 20 miles. If you avoid these, they taste great. In fact, my wife that grew up near L.A. and never ate wild game before she met me, says she prefers pronghorn steaks over elk....I think it's good, but I dont share this same opinion ha ha.
Good luck with your hunt, and have fun!!