When fletching I make the cheapest arrow possible to get started. From there I just make the next cheapest arrow with increased range until I am making 150 range arrows. Sometimes I'll make arrows with a slightly higher trivial to further raise my skill and improve success rates on the 150 range arrows, once you are at 90 skill the combine seems to be more or less as reliable as it will get.
http://wiki.project1999.com/Fletching includes a table that shows the stat mods different components result in and a table showing most of the possible combinations.