As far as in-flight noise Ashby recommends a solid BH with no venting to minimize. He also highly advocates for using small, straight, four- fletch feathers with a straight back (no parabolic or shield cuts) and finally the most important, no helical twist. I would think a solid BH with a long 3:1 type ratio would be the quietest but this is not based on any testing on my part, only from my online research and hunches. I ordered my RF Test Kit from Ethics and will begin my heavy arrow build journey soon. This has been and continues to be incredibly useful information thank you all for sharing!!!