You don't have to match the blades with the fletchings. It looks cool, but doesn't effect flight in the slightest. Depending on how long your arrows are and how much centershot you have you may want to orientate the blades so they clear the riser better though.

What you have heard works well on aluminums that use heat glue, however it will not work on carbons or aluminums with a stronger glue. The only reason I would rotate my inserts was if they did not spin true.

Paul