The enhanced magnetic field performance of smaller coils is valid for small gradient coils as well.  Applicable CapNMR probe models employ a small z-gradient coil that requires very little power (10-20% of full gradient driver power, typ.) to produce standard field gradient values (40-80 G/cm), and can be operated at higher powers to reliably produce gradient strengths of hundreds of G/cm for diffusion and other gradient-intensive spectroscopy applications.  Further, the use of a smaller coil geometry means that the fields produced are better confined and have less interaction with the magnet and surrounding structure.  This means less eddy currents and faster settling times, with less demand for complicated shielding circuitry.  Simple, effective, and efficient – the microflow way.