Depending on how you are doing your maintenance, a single guy will open and close the skirt. With the right leverage (you put your back to it, scoot your butt the level of the bottom, place both hands on the bottom, and push and lift at the same time), it's not that difficult to do in a clean environment, such as dusty conditions, or the motorpool.
However, if you are in mud, it's usually a two man job, and depending on how much mud, you will use the tanker's bar (5 foot pieces of iron) inserted into that bit at the end of the #1 skirt, and two will lift while one pushes.
You will never see an experienced tanker open up two skirts on the same hinge. The fear of having them drop on you is pretty significant. Total, the #1 and #2 weigh in the area of 1400 lbs, which is supported by a hollow steel pipe at the bottom, and a bolted on piece at the top.
Like Ric was saying, one guy will close them, then flip the half-moon around, and tighten the bolt on the half-moon finger tight, then insert the pin at the top.
Jed