The kinetics of nickel electrodeposition through a template of ordered polystyrene spheres is addressed experimentally and applied to prepare a series of metallic inverse opals with a non-integer number of layers. The observed layer-by-layer growth is discussed in terms of subsequently increasing disorder of the growth front. Reflection and transmission spectra of the samples demonstrate that the key optical features of these photonic crystals are most pronounced when the thickness does not essentially exceed two layers. The intensities and band positions can be additionally tuned by varying the height of the metal coating continuously, not discretely. These findings are confirmed semi-quantitatively by means of computational modeling of the spectra. Specific deposition current transients for in situ control of geometric parameters are discussed.