Repacking the MAST is not that big a deal. The seal kits are pretty cheap. It can be done in a couple of hours or maybe a little over with the learning curve.
I think all you need is a large crescent wrench, sockets, hammer, punches, pliers. You might need a way to lift the cylinder out if you can't pick it up by hand.
You jut put a block of wood under the mast and tilt it forward. That takes the tension off of it. Then take the cotter pins out, and knock the pin out of the chain. Take out 4 bolts, loosen the lines and its free.
There are detailed instructions in the packing kit for the cylinder itself. I would recommend changing the hydraulic filter at the same time, since you will have new fluid.
If you have any questions, I can probably answer them or you can talk to my mechanic. I have 12 lifts from 2000 to 30,000 lbs. so we have done this a few times