would a wobble extension help? i picked up a set of these for cheap at harbor freight, all different lengths. i had a similar problem spot and the wobble extension went in at an angle.
how about a makeshift cheater bar on the box wrench, i keep odd lengths of metal tubes for this purpose...
1993 300e-2.8 - gone now <sigh>
"Do not adjust your mind, it's reality that's malfunctioning"