The paper reports computations for Al@C82, Sc@C82, Y@C82 and La@C82 based on encapsulation into the IPR
(isolated pentagon rule) C2v C82 cage and also on Mg@C74, Ca@C74, Sr@C74 and Ba@C74 based on encapsulation into the only C74 IPR cage. Their structural and energetic characteristics are used for evaluations of the relative production yields,
employing the encapsulation Gibbs-energy terms and saturated metal pressures. It is shown that the results can be well related
to the ionization potentials of the free metal atoms.