on a Hunter we used for a photo soot for an ASA textbook.
It had an "out" string and an "in" string, and one of our "models" tried to unfurl the sail by hauling on the "out" string. What you have to do is haul on the clew outhaul and more or less let the other strings do whatever they want to do. You have to take up slack on the "out" string, but if you pull on the "out" string and not the outhaul, all you do is unfurl the sail INSIDE the mast. At some point, it simply jams. You then have to fiddle with the various lines until you've wound the sail back up snug and you can start over.
The "in" string, of course, must be unjammed and free to wind up on the spiral thingy in the mast or you'll break something. You can control the sail a little by putting one turn of the "in" string around a winch or cleat -- assuming Mr. Hunter has given you one in an appropriate location -- to put a little tension on it as it pays out.
You should not need much winch at all on the clew outhaul until the sail is out and you are beginning to flatten it. I once watched a bareboat charterer pull the clew right out of a mainsail on a 40-foot Jeanneau (the boat I'd just got off) because the sail had jammed inside the mast.
Read the manual and practice at the dock until you have the system down. It takes 3 or 4 people at the most to operate it effectively.
Oh . . don't forget to ease the vang and sheet when furling and unfurling. Steve Pettengill, who was for several years Hunter's designated boat breaker, told me that boat owners break more stuff thru, er, inexperience, than he ever could deliberately. (He was, at that moment, showing me rampant destruction caused by "inappropriate" operation of the in-mast furling system.)
You are a patient man, dealing with all these "teething" problems. Hang in there.