I saw one that used the item similar to a boat wench but used 2 cables, it was mounted on one side, and had pulleys on the top of each side at the top that the cable road in to make the change in direction.
One side had 2 one for that side and the one to run across the top to the other side, Then The other side had one for the cable to run down. The pulleys were mounted just above the top on the outer corners of the uprights. That way the cable was out of the way above the top and on the outside of each side rail. This was connected to the handles of each side with cable loops. This way you could raise it up lock it, while you put in the pins, Then unlock and lower it down on the pins. If you had good enough pulleys on good shafts you can even raise and lower with your parts on it. This way you could put them on at the height that was comfortable then adjust to what is needed. A plus for people with bad back and shoulders etc.