If you took an ordinary trainer and gave it a lifting stabilizer, changing nothing else, you'd get a plane that would fly badly, if at all. The Telemaster, which has a lifting stab, also has a large amount of negative incidence in the stab, to keep the total lift of the stab negative, as it should be on this type of plane. The OP, despite his degree in "aviation technology," seems to think that the tail of a trainer is supposed to provide positive lift. Since the original question was based on that mistake, it's not going to be possible to give him a satisfactory answer without somehow disabusing him of that notion. His basic intuition, that a lifting stab can be part of a design meant to keep the angle of attack about the same despite speed changes, is right: that's what the Telemaster design was meant to do. But you can't get there just by adding an airfoil to the stab.