I haven't gotten around into doing any large bods this week got about 1k cloth and iron's to do. But I had a theory before not sure if it was confirmed or posted before. But I remmeber I asked about it but never received a answer. Anyway I started on a mid skilled fletcher and used the quest to raise his to gm. I noticed I received oak,ash,yew and finaly a heartwood runic kit at comparable skill levels of my fletcher skill. I first received only oak then when my skill got higher I received oak and ash then as it increased I received yew,ash,and oak untill I received a heartwood when I was at gm. Might need another person to confirm this but this has being my observation while testing the theory that the runics are based on skill as well which I haven't seen mention anywhere unless I missed it.