Pneumatics limit?

Is there any limiting factors on pneumatics we could put on our robot, such as size and amount?

<R71>: any pneumatic cylinder up to 2" max diameter and 24" max stroke are allowed.

The size limit for actuators is given by the rule you quoted. The number of allowed actuators is limited only by the weight/volume constraints of your robot and the practical limit of the air you can provide to power them.

So very true, the real limit on pneumatics are that little compressor and those four small tanks.