Tong-ah Arrows

Im looking to see if there is a formula for the tong-ah arrow.

Formula, meaning a lenght, or weight of arrow based on the draw weight of the bow?

I'm really excited about trying this, but would like to keep the bow in one piece. If any of you have had a bow blow up on you, you know what I mean.

Generally I try to keep my arrows 7-8 grains per pound of draw weight. Going to be very hard to maintain that with half an arrow

Any thoughts or ideas, and experiences would be appreciated.

raven