For the carbon shaft thing look in that huge Sovereign GT Mods thread in the modification forum. At least one or two people did full length carbon fiber shafts on theirs, while using a Whites tall Man lower rod my shaft is about 75% carbon, using a lighter grade shortened aluminum shaft for my upper shaft. One of these days I'm going to replace that with carbon too, as well as a carbon bike end bar grip, which are cheap if you know where to look.
I bet you'll make some killer finds if your feet are slowing you down. We all hunt to fast, even if we make an effort to stand in place and only advance the coil an inch or so at a time, it never works out that way. Grass is always greener "over there". Hard to fight human nature. But I wanted to relate, that I read a story a year or so ago about a guy who hurt his back real bad and wasn't able to do much more that walk real slow like for a long time until it healed.
I remember him saying he hunted the trashy small patch of grass right next to the parking lot if memory serves, where he had hunted countless times before and thought he had got all the silver to be found out of there. Nope, because he pretty much stood in one place and only moved forward inches at a time, he ended up plucking more silver out of that small patch of grass than he ever had before. Again, if memory doesn't serve I might have a few minor details wrong but that's the whole point of that post he made- Think of the foot thing as your alley to force you to do what we all should be doing.
Heal fast...But hunt slow...
PS- Got to drive this into my head as well, in particular when using that 7.25" Tornado I just got. A coil like that ain't meant to cover ground, it's meant to snake around and seek out trash to work the edges looking for high tones. I'm trying to tell myself to not only let my feet grow roots, but also to work any trash or iron hits from several sides to look for any hints to a high silver tone in there. Plan to also grid at those odd diagonal angles to landmarks like sidewalks or roads or tree lines like nobody does. Again, just rubs human nature the wrong way to do that.
Last year a friend and I made it a point to do those odd angles and found plenty of old coins, both wheats and silvers, that would only sound off from those odd angles. We we check them from the "normal" angles and they'd either null or sound like junk due to masking. Really an eye opener, that showed us most people either parallel or they go at 90 degree angles to landmarks or such. Even though I'm sure this coil will unmask stuff bigger coils can't even using the "regular" angles, I figure if I grid diagonal it'll increase it's potential even more to find stuff everybody else has missed for years. Instead of gridding at the normal "+" angles, I'm going to do the odd "X" angles to landmarks.