AEA Plenum wizards please help.

Okay so I have an aea m457 that's regulated. I also have the pistol too. I was noticing the pistol air tube is slightly larger than the plenum tube. It's roughly an inch and eighth longer. I don't even know how to calculate CC's per inch but I was wondering if the increased plenum will help push velocity up easier per say? Id like to maybe get some feedback from owners before I even begin. I will have to get baseline numbers before I change anything. Thanks in advance and happy Labor Day.
 
To calculate the plenum , take the OD of the cylinder, remove the wall thickness. Take that number and plug numbers into this.

Now the general rule of thumb is for plenums is 1cc per ft/lb of energy. You can get away with less volume by increasing the regulator pressure but it’s gonna cost you shot count. You’d be amazed at how much power you can make with just 100 bar . But yes you make more with higher pressure.