Hello, Josh,
Rusted bolts/nuts/screws are par-for-the-course for these projects.
Dealing with clutch-head hardware is really no different than dealing with any rusted, stubborn old hardware (in fact, the clutch-head itself allows a better "grab" by a screwdriver, compared to other commonly used old hardware heads).
If you do not have clutch-head screw-drivers (or driver bits), use a regular flat-tip screwdriver that fits the clutch-head (or, grind a regular tip to tightly fit the clutch-head).
There are two Stovebolt.com Tech Tips
http://www.stovebolt.com/techtips/#bondo]on bolt/screw removal in the General Body Work section.
Patience, penetrating oil, and good use of swear words seem to help.
