Depends what fish. Soft fleshed fish power is less of an issue and avoiding tear off is a bigger issue thus should use a slip tip and realize that your impact point will change from floppered shaft. I haven't tried the 140cm Pathos but was disappointed with the 130cm Pathos ... the 120 Pathos worked great. Problem with the Pathos 130 was that it was shooting high due to the shaft doing wheelies and would lose penetration at distance (had less penetration than a 120 at 6 meters). It could have been that the shaft metal was too soft and thus going to 7.5mm would certainly be better. As for power, forget the default setup, my setup came with 2 x 17.5mm bands. You should take advantage of the amazing band stretch of a 140 (probably around 150cm of band stretch) and I would go 2 x 14mm or 14.5mm small ID bands at high stretch. The thin bands have less recoil and push the shaft faster which should give better shaft flight and better accuracy.