A lot of primitive archers use glass points. The only problem with them is that most people get just one shot per point. The points are easy to break. The best remedy for that is to make them thick.
The biggest concern on size of points is the limitations put on it by each state's game and fish laws. Be sure to read them first. The little "bird points" that were sometimes only an inch long were used on buffalo by the Native Americans. All the point needs to do is poke a hole in a lung, cut a big artery or puncture the heart. The lung will collapse and the other hits will cause the animal to bleed to death quickly.
Another concern is getting the points sized to the same weight. If the arrows weigh different amounts, they fly differently. The weight can usually be equalized by changing the length of the point or the design of the base.
WA