Wheel base in the distance from the center of the steering (rear) axle (or tires) to the center of the driving (front) axle (or tires).
Overall width is the maximum width of the vehicle usually over the drive tires.

If your concern is maneuverability - you need to look at the vehicles turning radius. For working on smooth surface concrete solid or press-on cushion tires will afford you the pest turning radius & narrowest width. Pneumatic tires are best when working on uneven surfaces (broken concrete surfaces negotiating over rail tracks, etc. A 45k lift capacity unit, cushion or pneumatic tire unit will tear up an asphalt surface, the cushion unit will do it faster.
Tire life is a function of operating surfaces, condition, operator, how often a unit is running empty - about 60% of the GVW is on the steer tires (which are smaller than drive tires) when the unit is empty and when steering they are subject to a lot of scrubbing pressures. You can expect to replace two sets of steer tires per each set of drive tires.