Presume you are asking about micro strip lines with specific impedance e.g. 50 ohm. For a certain substrate permittivity, lets say FR4 with 4.3 to 4.6, the inductance and capacitance per length unit will be always the same, independent of substrate height respectively ground plane "spacing". Height and width are simply linearly scaled. The main advantage of thinner substrate is smaller trace width, on the other hand, losses will slightly increase.
You can use the Saturn PCB toolkit to calculate impedances and specific L and C for strip line geometries.