A 121 inch with 1 inch lug is what you want.... A camaplast Hacksaw as just under 1 inch lugs, and you can stud up to 1.098 with will be plenty, you can go up to the 1.25" lug RIPSAW but it will rub on the front heat xchanger. and running studs wouldn't be smart with that track unless you get smaller drivers.you would want smaller drivers in general if you would get a 1.25 track to get the clearance.
110 Mph across Lake with my 2001 srx700
i have a 1.25 track on my 99 vmax 600, and 3 1/2 drop brackets, it was rubbing real bad, couldnt tell were it was rubbing at, there was black on the tunnel protectors and some down ward rub marks on the front heat exchanger, track was loose with 3 or mor inch with weight on center of track, so thats no down to 1" of play, but could it be the track size like u said, even with 3 1/2 drop???