RE: Fletching Question
Helical will definately cause the tips loosten up.If your arrow is hitting a target and spinning when hitting the target,the tip will be in the target and have a force applied trying to hold the tip from spinning but the shaft will not have a force trying to hold it from spinning so the arrow will loosten up from the tip.
This isn't that big of an issue and string wax will all but eliminate the problem but it is true.Go with right because they are generally easier to find and the tips won't be as likely to loosten up.