Hi Infantry Soldier,
The best equipt person to answer your question is a member who goes by the name of Super 91. He has been shooting the TAC 15
and 15i for at least 3 years now.
He's done more testing with a multitude of different vanes than the rest of us all put together.
Super 91 is one of only 3 field testers for Aerovane and Aerovane II's, but he has also done extensive testing of these vanes against everything else in the market place. He keeps great records on all his test work, so he could give you the help or information that your looking for.
I'll let him know that you have a few questions and see if he's able to break away long enough to jump in. With hunting season fast approaching and the new Drop Away Rest that he's testing, he may be pressed on time for a while.