I have not seen those Trinity narrow tires available.
Inspgadgt. I agree with you that there is more camber change with roll with that short arm and I did state that short arm as one of the three important differences in the two suspensions.
I do believe that most of the magic is somewhere else, though. I have tinkered with the upper arm length on the touring cars and it makes but a small difference. The RC cars in general are insensitive to camber changes. That's why we make camber changes just to even the tire wear. The difference in performance between the two front ends is dramatic.