One aspect of the teachings herein relates to signaling codebook restrictions, to restrict the precoder recommendations being fed back from a remote transceiver, so that precoder selections made by the remote receiver are restricted to permitted subsets of overall precoders within a defined set of overall precoders, or to permitted subsets within larger sets of conversion precoders and tuning precoders, for the case where the overall precoders are represented in factorized form by conversion and tuning precoders. As a non-limiting example, these teachings advantageously provide for precoder restrictions in LTE or LTE-Advanced networks, where ongoing development targets the use of larger, richer sets of precoders, and where the disclosed mechanisms for determining, signaling, and responding to subset restrictions provide significant operational advantages.