Have you shot the same arrow with a field point then unscewed it and screwed in the montec broadhead? What happened? Did the field point fly perfect, and the broadhead wobbled? If so make sure its screwed in straight and tight. Does your broadheads have washers? Some broadheads are radiused, where they meet the arrow insert and must have the washer to sit flush. Your arrows to me seem light for 60#. The 4" feathers may be the fix. Go see Ross and have him fletch one or two arrows with the 4" inch feathers and let us know. Also you may want to crest the arrow just to add a little weight to help steer the arrow. Kinetic energy is more important them speed. Speed is good and all but penatration puts the animal down.
Good luck and good shooting
The same arrows with field points fly perfect and are damn accurate for me. I think I will get some washers. Other than having them seated right, they might help me get the broadhead blades ligned up with the fletches. I heard that this could help. Hopefully the Hanna will be out of here and not too wet to go shoot some tomorrow.