  We have synthesized and characterized four different stable phases of Na
ordered Na$_{x}$CoO$_{2}$, for $0.65<x<0.8$. Above 100 K they display similar
Curie-Weiss susceptibilities as well as ferromagnetic $q=0$ spin fluctuations
in the CoO$_{2}$ planes revealed by $^{23}$Na NMR data. In all phases from
$^{59}$Co NMR data we display evidences that the Co disproportionate already
above 300 K into non magnetic Co$^{3+}$ and magnetic $\approx $Co$^{3.5+}$
sites on which holes delocalize. This allows us to understand that metallic
magnetism is favored for these large Na contents. Below 100 K the phases
differentiate, and a magnetic order sets in only for $x\gtrsim 0.75$ at
$T_{N}=$22 K. We suggest that the charge order also governs the low $T$ energy
scales and transverse couplings.
