5 gpi seems a little light. Arrows are something you should do alot of homework on. Not only do you want the correct spine but your FOC has alot to do with it. Some people will tell you they like light arrows for speed where others want a heavier arrow for penetration. With a light arrow you will feel the bow more and a heavier arrow will take some vibration from the bow. You could write a book just on arrows. Get some arrows between 7-9 gpi and to start you out, then start experimenting with other arrows. Find out what you/your bow likes.