  Naturalness arguments applied to simple supersymmetric (SUSY) theories
require a set of light higgsinos with mass $\sim |\mu|$ not too far from $m_h$.
These models have an inverted electroweakino spectrum with $|\mu| \ll M_2$
which leads to a rather clean, hadronically quiet, same-sign diboson (SSdB)
signature at hadron colliders arising from neutral-plus-charged wino pair
production. We improve and expand our earlier studies of this signature for
discovering SUSY in natural SUSY models by (i) including backgrounds which were
not previously considered and which turn out to be significant, (ii) devising
more efficient cuts to successfully contend with these larger backgrounds and
determining the discovery reach and exclusion ranges for winos with these cuts,
emphasizing projections for the updated integrated luminosity target for HL-LHC
of 3 ab$^{-1}$, and (iii) emphasizing the utility of this channel for natural
models without gaugino mass unification. We display the kinematic
characteristics of the relatively jet-free same sign dilepton+$\not\!\!\!{E_T}$
events (from leptonic decays of both $W$s) and find that these are only weakly
sensitive to the parent wino mass. We also examine the charge asymmetry in
these events and show that its measurement can be used to check the consistency
of the wino origin of the signal. Finally, we show that -- because the wino
branching fractions in natural SUSY are essentially independent of details of
the underlying model -- a determination of the rate for clean, same-sign
dilepton events yields a better than 10% determination of the wino mass over
the entire mass range where experiments at the HL-LHC can discover the wino
signal.
