Looking at the specification of the new trek model vibram sole and liner adds up to 8mm I can feel the difference going from less than 2mm 'KSO' to 4mm 'Flow' models, so the Trek should certainly help with stone bruising problems.
As I remember the legend the original five fingers were designed as deck shoes for the Med. maximum feel therefore minimum thickness to avoid tripping over deck fittings.
An interview with the (still breathing) silver whistle blower fascinating stuff.
"paper hundreds : silver / gold 1", says man from Goldman Sacks - whoops apocalypse, LOL.
Another day, another run, then down to my neglected allotment to plant some seed potatoes I fully expect to get a 10 : 1 yield ;¬)