Unfortunately we don't get to decide this. The rifle will tell you which is best after you shoot a few. You may have better or worse accuracy with several different brands.
Just out of curiosity what are you hunting that needs solids? Only a very few animals require them in a 375HH. Rhino, elephant, and hippo. Even then you can do nicely with a bonded core soft point. Buffalo do not require solids and actually die faster and in shorter distance with softs.
I suppose the happy meduim would be the Barnes X bullet. Its a solid that will expand a little bit. I don't have great accuracy luck with them in my hunting rifles but in my work rifle the 458Lott they shoot awsome. Unless you're shooting one of the three tihick skinned animals I listed above you really don't need to load solids. I might throw in Giraffe with that group too. They have skin in some areas thicker then all of the above listed animals. They are also very difficult to follow up and locate once wounded. Giraffe are by a large margin a more difficult to kill animal then a bufflao. Most PH's will work very hard to get you a head shot. Body shots are just soaked up and they run like crazy. I have personally seen Giraffe shot 6 times with a 375 into the body and still stand or run. Its a greatly underestimated animal for toughness.
