The aircraft is certified at 2.4% for the 2nd segment. Within its flight envelope it will always make this. This is simple regulations. And you cannot depart outside the aircraft limitations (to which the aircraft was certified) under any normal circumstances.
So the only thing that can be done is finding more performance (new certification), reducing weight or finding a regulator that will allow you to operate outside AFM limits.
The gross flightpath is simply the takeoff flight path that is ACTUALLY flown by the aircraft (starting 35ft above the end of the takeoff distance)
The net flightpath is the gross flightpath minus a mandatory reduction of 0.8% (twin)
The net flightpath ALSO has to clear all obstacles by at least 35ft
The climb limit therefore only arises when the gross flight path minus 0,8% (net flight path) does not clear all obstacles by at least 35ft.
The 0,8% is therefore an extra safety margin (I guess for mishandling) on top of the minimum obstacle clearance of 35ft. It is not the obstacle clearance itself.