RE: blazers straight or off-set
Are you referring to your blazers parallel with the arrow shaft or at a slight angle? I believe that with any tip, fixed or broadhead you will want some sort of offset, be it an angle or a helical (the rear of the vane to the left or right of the leading edge of the vane).
Watch a football in flight, one that spins is more accurate that one that doesn’t. That's what an offset shoud accomplish.