The best set is the one that you can buy it hehe
I made a comparison of the spiritthorn with my actual items and decide to not use full spiritthorn.
The spiritthorn helmets protect energy damage, so if you don't hunt creature that hit energy should be better use another one with some imbue.
For example: to hunt werelions it be better to use falcon coif with imbue of skill and leach than spiritthorn.
It's a basic example but I think that this is the way
Put in balance the Elemental protection of equips because kina hunt with boxes this protection does difference.
PS: For my Kina lvl 573 there is no difference when I hunt werelion with spiritthorn armor, helmet and when o hunt with falcon coif and lion plate the final exp is the same.