I use my A/C all the time and the air volume is a little low, compared to all of my new cars. I was going to use a relay to drive my blower directly off of the battery when I have it on high. You can try the same thing by using a big supply wire and hooking it directly between the battery and the blowers supply wire. You can get to it on the engine side. Compare the air volume to when you have it going through the switch. You'll see that you are losing current through the inside wiring.
I have 3 A/C e-bodies. There really aren't any filters in there to block anything. If all your vent deflectors are deflecting when you hit MAX A/C on your panel, and you don't have any mouse hotels in there, or leaves in the motor's fan blades, the system is usually cold enough to chill you out. Is yours not cold enough?