RE: helical twists?
To prevent planeing of an arrow especially when using fixed blade broadheads you need to get the arrow spining as quick as possible out of the bow and that is where helical fletching comes in. The left/right isn't relative unless you shoot a helical bladed broadhead then it is important to match helicals or your shooting off the shelf of a stick bow or shelf style rest on a compound. Some will say they perfer a right helical so it doesn't spin opposite the threads of the broadhead which they say loosens the tip but shooting left helical, I've never had this problem. Also, I haven't had helical fletch tear off any more or less than straight fletch if done properly.
I perfer and recommend a helical fletch in conjunction with a fixed blade head to optimize stability of the arrow for tuning, however unless your having a problem in that area, you needn't change. You can and I also recommend an offset fletch.
The one downfall of helical is greater clearance needed on shoot through style rests and depending on the size of the arrow, this is sometimes difficult.
<font color=blue>Good Luck and Good Shooting</font id=blue>
<font color=red>Rob</font id=red>