If you could make an extra long arrowhead, so the shaft doesn't reach the wood and can be unscrewed from the head, then you can cut a thin slice around the arrowhead and split the wood off of it. In that case even small barbs should be fine, like cones or something you would find on plastic screw anchors. The very tip of the arrowhead might best be rounded and not very sharp for best penetration, otherwise a long sharp point will just add surface area for friction. I think that is why round nose pellets penetrate so deep compared to the sharp pointed ones.