Spent all day at the hangar today finishing up the wiring to the wings and tidying up the panel wiring. Used my engine hoist and one of my steel beams to rig up a support for wings during installation like other folks have done. Also protected the rear spar from the straps with 2 by 4 blocks. This rig worked really well until I noticed my straps started to slip over the top of the steel bar and wing began to rotate .. I had a hangar neighbor stop in just in time to help me stabilize the wing down to saw horses. Could have been disastrous. Solution was to wrap several loops of duck tape over the strapping securing them to the steel bar to prevent any rotational slippage of wing. Tomorrow begins the progressive trimming of the wing skins to bring the spar holes into alignment.