I would use a 180 or 200, but if the 165 Barnes is what you know, can shoot accurately and place shots well, then go for it. I've not tried Barnes X but it looks tough and retains weight. The only negative I've heard is losing petals when pushed too fast, but shouldn't be an issue with a .30-06. i'd be happy up to Kudu but would definitely go heavier from there on...
Have a great trip!

Grandveneur - I'm looking forward to a report and photos!