About a week ago, I posted a vane thread titled "vanes: offset vs helical" and you can go there ----> http://www.huntingnet.com/forum/tm.aspx?m=1503238
Most of those questions are answered! In regards to wraps, they slightly weigh down your arrow, but you get better adhesion when you vanes are glued to the wrap instead of the shaft. There isn't anything wrong with glueing straight to the shaft. Another plus about wraps is there isn't all the scraping and sanding to get all the glue off...just pull the wrap off, however, if one fletching needs to be re-placed, they all get replaced.