I would be very concerned about placing the forestay farther up from the attachment point of the shrouds. This will give the mast a tendency to bend forward at the top and could wreak havoc on trying to maintain sail shape in rough water. With everything attached at the same point, the mast is free to bend with downhaul and mainsheet tension and the bending pivots on the tang where everything is attached. With the forestay higher, it will fight the bending effort.