[Kevin Sevcik]

As GeeTwo said, you should be able to calculate your air usage. If you're only using it for shifting, you can probably get by with one or two 36 cu in tanks. A single tank would get you 160 actuations of a 3/4" x 1/2" cylinder at 60 psi. So 40 low-high-low shifts for a double acting cylinder. 80 for the Andymark spring return cylinder. Shifting from low to high and back every 3 seconds seems reasonable, unless you have really aggressive auto shifting. If you can drop the working pressure to 40 psi without shifting too slowly, you can double the amount of actuations. 50 psi = 40% more shifts.

An onboard compressor isn't really going to save you much space, because it's big and you'd still need some sort of storage tank. A 36 cu in tank is 12 x 2.7, 88 cu in if you call it a box. The compressor is 2.1 x 4.5 x 6, 57 cu in as a box. So it's pretty close on volume consumption. You'd probably be better off running 2 tanks and no compressor than 1 tank and 1 compressor. You'd definitely be better off running just 1 tank.