No way they're too weak, Joel. Definitely overspined, but they should shoot much better than what they're doing for you.

I would get rid of the thick strike plate and go with thin leather. No disadvantages at all with leather instead of sealskin. I prefer leather, myself.

You also have to take the bow's feelings into account. Some bows simply do not like shooting certain types of arrows and get mighty upset with you if you try to make 'em do it.

Have you tried any wood or aluminum arrows out of it?