You shouldn't need to worry about injuring yourself messing with the shock. The gas pressure is very high, but the quantity of gas is so small it's insignificant.

The process of charging up the shock is simple if you have a tank and regulator. I know people who do it themselves.

Any decent suspension shop can tell you how much pressure to run. I don't recall but I think they carry about 300 psi. Maybe someone on the list knows for sure?