  Four groups (even-even, even-odd, odd-even and odd-odd) of heavy and
super-heavy nuclei are of interest for the synthesis of the isotopes with
$Z=119, 120$. We report calculations of $\alpha$~decay half-lives using four
models: AKRA (Akrawy); ASAF (Analytical Super-Asymmetric Fission); UNIV
(Universal Formula), and semFIS (Semi-empirical formula based on Fission
Theory). We compare the experimental $Q_\alpha$ values either with AME16 atomic
mass evaluation (whenever available) and with the theoretical model WS4, able
to give masses of not yet measured nuclides. For $^{92,94}$Sr cluster
radioactivity of $^{300,302}$120 we predict a branching ratio relative to
$\alpha$~decay of -0.10 and 0.49, respectively, meaning that it is worth trying
to detect such kind of decay modes in competition with $\alpha$~decay.
