25 grains won't make a ton of difference, but when in doubt, use a little more weight on your arrow tip. So I'll go with the 125.
I've broken the strings several times with this raven. I was thinking a heaver broadhead would help take some shock out of the system.
I shoot 150 grain broadheads on the crossbow that I have for my wife and kids. Crossbows shoot so fast that you are not losing anything with a heavier broadhead up front.