simon, lets keep it in context of racing 500/550's fours and try to help this guy....
So yes, of course that if you are not sliding you are not going close enough to the limit but at 48 years old, I am happy to do it only once or twice a lap in the corners I feel good at. I applaud your young gun (or is it you?) for being able to keep it on the edge it all race long.
In any case, to put my comment in context, I did not experience any WORSE rear traction problems when I raised up the rear a good 1"-1.5", that was all I was trying to tell our friend. I think that raising the rear in a 500 is beneficial, lowering your front instead will rob you ground clearance. (And of course you can never have enough grip
)
Then, a 100 kg, 50HP 125 with a 55 kg rider is very high power compared to a 150kg, 60hp 550 (if he has that kind of power in the first placer) with an 75kg (85kg in my case) rider in top. Your 125 has a power to weight ratio that is
50% higher, so yes, a a racing 550 is very low power compared to it and the type of problems are vastly different. Some info will apply, some not.
TG