Same group and load IMHO, so you pick the Hornady? For a .375? Go with the Barnes for Africa and the Hornady for America.
2 cents (and good shooting there)
I am going to do exactly as you are recommending.... right now, I am not planning an African trip, and will be shooting moose and elk with this rifle. Therefore going to use the Hornady which is most-accurate out of this barrel at all fps levels.
If Africa ever becomes a reality (not in near future) I will load the 75grain Barnes.
Good advice from you!