Va Elite,
you need some system of tuning the arrows before you ever decide how long, etc.
What i always do with a new arrow is pick the weight head I want to shoot. Usually around 175 or 200 and then tune my arrows to that head.
I always tune my arrows by bare shaft tuning from around 12 feet and let the arrow tell the tale. All you need to remember is nock left = weak, and nock right = still. if it is weak, lighted the point or cut a little of the arrow off(what I do). If it is stiff, add more weight up front. It can be tough adding inches to your arrow so cut wisely.
Always shoot several arrows before making any adjustments.
Reality is that with you just starting out, tuning an arrow perfectly is going to be one of your greatest challenges. You probably don't have a set form or routine yet so your consistency wont be that great, but don't get discouraged. Everyone of us started of like that, you will get better with time!