RE: arch in arrow flight.
Then you must not have the bow set at 70#. Those arrows should be flyin pretty flat at 20 yards. See if the bolts that hold your limbs onare screwed all the way in. If they aren't screw them all the way down and try it again.
I have a guardian set at 71# and am shooting FMJ's, which are pretty heavy arrows. It is hard to follow them at 20 yards they are going so fast. And no noticable arc either.