This study presents effective (mass-dependent) potential energy curves for the methylidyne cation, which reproduce highly accurately all the available spectral data and allow for evaluation of reliable ro-vibrational wavefunctions of the probed isotopomers. The ro-vibrational wavefunctions are then used to average ab initio calculated radial functions of the rotational g-factor and spin-rotation constants yielding rotational and vibrational matrix elements of these properties for specific ro-vibrational states or transition moments for all isotopomers. The results can be of use in answering open questions concerning the formation/destruction of CH(+) in the interstellar medium and in the assignment of Zeeman or hyperfine splittings in rotational spectra of CH(+).