Strutter.. since you want to shoot a Black Diamond XR might I suggest something totally different in the conical line up. The conicals I shoot and hunt with out of my Black Diamond XR is the 460 grain No Excuse Conicals.
That group was shot off shooting sticks during deer season two years ago. I was going to change hunting locations and was loaded with a 375 grain Buffalo Bullet SSB (smaller hole on the far right) so I shot that off, then fired a couple No Excuse Conicals without swabbing I might add to make sure it would be dead on for the afternoon hunt.
These big conicals will work on deer, elk, bear, you name it and they work. As for which is better or more accurate out of Hawkins, the maxiball or maxihunter, I have better luck with a maxiball. That does not mean the next Hawkins down the line will be the same. It might not even shoot conicals at all very well. That's one thing I learned after many years of shooting black powder rifles.
Today I was shooting minnies and ball-ets out of my .58 caliber 1-70 twist. I was shocked at the poor accuracy the minnies were getting. I really thought they would do better. They were 315 grain which did pretty good, and some 500+ grain things that I have no idea where they were hitting. The 405 grain ball-ets on the other hand did very well. That is the only way I ever found, that I can determine if a projectile will shoot good out of my rifle.
All you can do it try the different projectiles in your rifle and see which one works for you. Try and choose the projectile to match the game animalyou are hunting and you will be fine.
Besides, that give you a good reason to go to the range and shoot a lot. Good luck with your rifle and keek us posted.