remember that some parish records eg Lezayre only exist from late 17th century (see http://www.ee.surrey.ac.uk/Contrib/manx/famhist/genealgy/church.htm ) - once at this stop point then wills may help as might manorial roll records - all on Mormon microfilms - eg are they recorded in any of the Manorial rolls if so by tracing the tenants back you may get a good indication of family