RE: Medium or hard cam?
Hard cam for sure.
I have a RazorTec as well and it is somewhat of a overachiever with respect to the KE it develops.
I would consider that a .340 arrow should spine just about perfectly for you if you leave it at about 29"
I shoot mine with a DL of 29" and 70# with .330 spine arrows at 28.5" and they tune about perfectly.