BootyBay, I had a M6 for about a year and took me some time to learn it even thou there aren't that many buttons. Some areas I could run that stock coil wide open. Others I had a heck of a time running the 5.3 coil 1/3. It seems so chattery some times it will drive you nuts, but good targets always seem to come threw.
If I hadn't had the bug to get a new XLT to try I would still be using the M6. Infact, if a spot one at a great price I plan on grabbing another one. Its great coin and jewelry machine. Put that 5.3 coil on it and its a great trash area machine to. I found a ton of clad with it and over 10 real nice rings along with other jewelry.
If it seems to get to chattery you might try pulling out the battery while the machine is still on for a few minutes. I tried this a few times and it really seemed to quiet it down. Guess it does a reset on the board when you do this. Also, if you try Discing out to high in some areas it will get noisey on you. Better off just discing out iron and sorting the rest out by sound, ID and repeatable signals.
Good luck with it and will be watching for more post by you in the find section.