Fitting a multi-channel cochlear implant system to an implanted patient is described. A fit map database is accessed that contains parameter data from fit maps of previously measured cochlear implant patients. For subsets of signal channels in each fit map, an average deviation is established between estimated parameter values and measured parameter values across signal channels not in a given subset based on measured parameter values of signal channels in the given subset. For a given number of signal channels, a subset of the same number of signal channels is identified that has a minimum average deviation. Then fit parameters for signal channels in the identified subset are measured and fit parameters for the remaining signal channels not in the identified subset are estimated.