The reality of finding records in Ireland - online or otherwise- for the 17th century is that that there might not BE any. Most people -including the nobility -in this era could not read/write and the recording of individuals who were not highly influential was not considered important. The recording of Births/Marriages/Deaths only really began to be widespread after 1800.
If you haven't already you may try:
I wish you the best of luck with your search.