XV750 and TR1 have different forks. The first is a 36mm diameter and the latter a 37mm fork. Also, if you're able to feel the difference of 14ml fluid, you should probably NOT ride a TR1, but apply for a motorcycle road racing series.
Also depending on your weight and whether you plan to use the air-assist or not, you may want to add even more oil as well.
(I've run XS1100 forks in my TR1 for close to a decade now, so I am not sure how much oil I used to use in my TR1 forks, but I think somewhere in the ballpark of 15 percent extra oil.)
Cheers,
Greg