Kalibrgun cricket.25 advices

[Kaptur]

I ask for your advice, I have a cricket 2 smooth .25, 600 mm unchoked barrel. I use 34 grain jsb at 870 fps. I can use  two pre-chambers, one 40 mm and one 60 mm (length). The air consumption per shot ranges from 2.5 bar to 3 bar and it seems high to me. I would like to know from you the best setting for regular consumption, i.e. valve spring tension, best regulator pressure and which pre-chamber to use. Thanks for what you tell me.