It real hard to get GT Arrows to 6 grains per Lb. and spine out right with 100grain tips.
When the 125 hits 6" to the right is that with a BH or field tip?..if BH what head are you shooting?...and yes you will need to re-tune the bow.
The 125 broadheads are the ones shooting right 6". The 100's are only off about an inch compared to 100 field points both with 5575@26". All shoot close to the same irregardles of the brand I have. 3 blade muzzy, Buzcut 2 blade, Buzcut stingers and G5 montec. The groups are tight and the walk back is vertical, right on the tape out to 50 yards.
I may just be over thinking it. My next thought is to just run it up to 70+ lbs, buy 7595 in camo and 125g tip. Thats 443g legal and hopefully spined correctly.
Don