i assume you want to reduce the rate of flow thinking it will reduce clamping pressure and keep your operators from crushing your product? Am i correct in this assumption?
This is a common problem with clamps that are not installed correctly with the correct flow regulation.

Your best bet is to get with cascade and obtain a flow regulation device. They sell many different types, manually controlled and now electronically as well.

Simply adjusting the pressure/flow may gain you some control over this problem but it also may create other problems with other functions. Generally the 3rd and 4th functions are called auxillary functions and are both controlled by the same flow regulator, or possibly they MAY have individual flow controls but you still donot gain the desired result due to the mfg limitations or lack there of. And furthermore Slowing down the motor control does not cure this problem, it just makes the clamp operate slower. Motor control adjustments do not change the pressure, they just change the flow speed. You still will have the same clamping pressure. Changing the size of the hose even though it will gain you some relative drop in speed you still have the same clamping pressure overall but you also create the problem of possibly blowing a underrated hose if you drop the size of the hose too much.

I understand you want to come out of this as cheap as possible to save money but it has been my experience that you get what you pay for. If you cheap out on the job you will not be satisfied with its results in the end. Do it right the first time. Get the right pressure control hardware for the attachment.