Umm, it's tough but it can be done. One thing to consider, if worse-comes-to-worst, is the fact that you don't absolutely have to loosen the locking nut if you're cranking the bars. The nut only provides tension against the bolt loosening, not tightening, so it should spin freely on the bolt if you give the torsion bar adjuster bolt a half-turn or so. Just crank the side up and then you should be able to reach in and torque the locking nut down with a smaller wrench then you'd need to break the nut loose in the first place.