With rosewood boards, and other hard oily wood (brown ones, basically) lemon oil is the thing. But the 51 is an all maple, so should be varnished, oil will discolour it, although I've just spend a week feeding danish oil to a maple bass, and it looks lovely. I think you wanna get a bass, then ask about specifics of maintenance. If it is poly finished, like most modern ones are, a cleaning should be all it needs.