I can only tell you, if you let me come hunt with ya, hahaha! .25 is the one caliber I don't have for my Maverick, but one of the guys I shoot with has one in .25. He was getting pretty good results with the standard superior liner that came in his shooting the NSA 33.5 grain in .250 I think. I believe he had the second reg at 150 bar with the one at the bottle around 170 bar. That was getting those slugs around 950 fps, I think. He has since swapped over to the superior heavy liner, and is shooting the heavier NSA slugs around the same speed, but at 85-90 fpe(with a little higher reg setting).
If going for a pig(head shot only recommended), I say setting the regs at 170/150 bar would be a good place to start. The rest will come down to adjusting the hammer adjuster so that your max power is achieved with the power wheel on 7. If you make a post about it in the PCP section, I'm sure some of the guys with a .25 Maverick will chime in on their settings, and probably be able to give you more specifics on the .25. The Maverick is a very capable platform, so the hard part is just figuring out what ammo and power level you want it to shoot at Obviously, you want to go with the highest power you can, and still remain accurate, if you want to go after a piggy.
Thanks! It took me a long time, before I was able to get the FX gun I wanted. It was totally worth it though. Being able to have regulated gun that can make the power the Mavericks and Impacts can make is really awesome! I've got a 300 bar bottle on my Maverick now, and it's even sweeter