My overall opinion of the 7.6FX = Great Bike for road and paved - path. Probably not so great away from asphalt. I would be more concerned about side - side traction with the smooth 28 width tires and bike slipping out from under you.
The rims are double walled with the hard case tires so puncture should not be an issue and you should have margin to prevent damaging rims assuming one does not go mountain biking with it.
7.5FX has 32's, but feels as good as 7.6FX on road. More traction. Wife has the 7.5, while I have the 7.6.
If majority if riding is road, I would get 7.6FX. There is room to put higher traction, wider tires if you find it's needed. This is something I am considering for the winter.
Hope that helps.