Practice ALL your shooting completely offhand. When you get there they will be using shooting sticks ( similar to a tripod) When you are accustomed to shooting offhand, ANY type of rest seems luxurious and easy...
Practice a LOT! Before my wife first trip she put right at 400 rounds through her '06 wearing a 2.5Xscope. All offhand. End result, 7 one shot kills...
All the ammo/ reloading component costs are cheap in comparison to a lost trophy fee...
