  Sky-coverage in laser-assisted AO observations largely depends on the
system's capability to guide on the faintest natural guide-stars possible. Here
we give an up-to-date status of our natural guide-star processing tailored to
the European-ELT's visible and near-infrared (0.47 to 2.45 {\mu}m) integral
field spectrograph - Harmoni. We tour the processing of both the isoplanatic
and anisoplanatic tilt modes using the spatio-angular approach whereby the
wave-front is estimated directly in the pupil plane avoiding a cumbersome
explicit layered estimation on the 35-layer profiles we're currently using.
Taking the case of Harmoni, we cover the choice of wave-front sensors, the
number and field location of guide-stars, the optimised algorithms to beat down
angular anisoplanatism and the performance obtained with different temporal
controllers under split high-order/low-order tomography or joint tomography. We
consider both atmospheric and far greater telescope wind buffeting
disturbances. In addition we provide the sky-coverage estimates thus obtained.
