I recall putting a box wrench straight into the bracket with the bolt head, 90 degrees to normal usage, and letting it rotate until it hit the sides of the bracket. It took a bit of pressure at that point towards the bolt while tightening the nut to get it done. You can also go to Home Depot and buy cheap sockets individually, then grind down the sides to make it fit...a bit more work.
As far a torque goes, calibrate your hand with a torque wrench somewhere else by holding it the same distance as the length of the wrench you will use. These won't be the last nuts that you can't use a torque wrench on. It is even more fun re-tightening these during annual once they are installed on the plane!
Gil's suggestion would work too, but you would have to install the bolts backwards and will likely hit the aileron bracket, especially the lower one.... Those nuts come in handy at times, or should I say critical!