Flatlander, we have an 18" Xcoil and if you were near i would lend it to you to try.
They are in my opinion the ducks nuts.
You are welcome to pm or ph me for more info about these coils. I am honest about the 2 I have and have no reason to bu!!sh!t about them.
Give davsgold a phone call as he is selling them here for maker and have a chat with him.
If you want a contact to do your lead i can give you the name of guy doing them in adelaide or dave or Kon61gold could help you as well. Also chat to kon as he will give you his thoughts and impression on these coils. He changed his mind after being the biggest sceptic of these coils when they first surfaced.
Good luck with your decision. TG