I have always used 100-grain broadheads, but am wondering if 125 would be better. I am currently shooting a Triax @ about 65 lbs with a 28.5″ draw. My arrows are Gold Tip Hunter Pros (340). I have shot Montecs for the last few years, but I am seriously considering the Slick Trick Vipers. Thanks in advance for any help.

The difference between a 100 grain and 125 grain broadhead isn't much and most people will never notice a difference in penetration or point of impact from 0-30 yards.  Beyond that, you may see a very slight difference in POI, but again, not much.  If you're looking to increase the weight on the front of your arrow, look into Gold Tip's FACT system.  They are small weights that screw onto the back of your insert and allow you to add weight to the front of your arrow without having to change broadheads.  As you may find out, broadhead selection can be limited at 125 grains.  The FACT system is nice because you can experiment with different weight combinations and find the one that works best for your setup without changing broadheads.

As for broadheads, both will work if you put them in the right spot, so it's all personal preference.  Focus on shot placement and everything will work out. ~ Justin