What type cable and size should I use for my shop?
We simply need more information:  How far to the shop?  Is the meter base at the shop?  A picture/diagram of property would be helpful; include distances.  

If the panel shown here is equipped with a main breaker, there is no need for an additional disconnect.  I see no need for the pole as all.  Just strike to the mast. 

If it is indeed 400-feet to the meter base you are going to have a fairly serious voltage drop problem.  The voltage is based upon the amount of actual current used at any one time.  

If the pole is required for ground clearance than don't splice at the pole just strike to the pole and continue to the weather head.  

Technically you need a quad-plex or 4-wires as the feeder.  After the service the neutral is separated from the ground. I would recommend an underground feeder.  I would put it down 4-5 feet for protection.  

If you could give me the estimated max current draw at any one time we could recommend a wire size. That means that when you strike an arc with the welder what is the actual current draw of the welder on the circuit.  And when the pump actually runs and is pumping full bore, what is the current draw on the pump motor. And when the compressor is running nearing the shut-off point what is that motor drawing.  And what is the actual amp draw on the lights? Then throw in 10 or 12 amps for power and bench tools per number of men that will be using the building at any one time. With this we can give you wire size.  

Do you ever plan to heat the building?