Try using 15N edited NOESY and TOCSY, these are very complimentary to the triple resonance experiments. Also - in the case you have overlapped peaks - look at them in all three dimensions, that way you can resolve them better. Sparky allows switching the axes on the display plane easily. Command **xr** rotates the spectrum in 3D, also it helps to center view on a peak before rotations - select a peak and then type **vc**.