Read buffalobob's post on 'lope shooting.
Poison Spider Antelope
Also look at the post did on the Oregon Trail antelope.
Both will give you some insight.
If a 115gr berger will do the job beyond 1K what you're shooting will certainly do it at half of that. The important thing is hitting with that first shot.
If any practice is needed between now and your hunt I'd stick a target on a dusty bank at 500-600 yds and only shoot during windy days. Heck, your not wearing out the rifle, its fairly inexpensive to load and fun to shoot. Plus you'll learn to dance with the painted lady or the wicked witch or just plain "that damn'd wind';)