It depends on on how under spined over spined you are then you can decide on head weight. More eqauls weaker spine less eqauls stiffer spine. You need to think of this before you buy the arrows. But there are other thingsyou can do if you want the 125 gr. head. I would suggest playing with your draw weight a little bit. As for the broadhead brand I use Muzzy three blades and have no complaints. H ave not used your magnus ones so I cannot compare.Good Luck and Good Hunting