What type of rest are you using, and how long will the arrows be? And are you sure about the draw length and poundage. I mean was it actaully measured and weighed, or are you just going buy what the bow says it's set on. Mathews have a tendancy to draw a bit long and go over on poundage. If you have 70 lb limbs and they are bottomed out I'd be willing to bet you are drawing more that 70 lbs.

Give us these details and people can start giving you some good options on arrows and tip weight. We need the ACTUAL draw length, draw weight, and arrow length in order to pick the correctly spined arrow though. These are very important things to know about your bow.

I'm assuming you want to stick with carbon arrows? What kind of fletches, feathers or vanes?

Good luck,
Paul