The Consolidated Index to the Records of the Genealogical Office by Virginia Wade McAnlis is a 4 volume Index of the documents in the Genealogical Office of the the National Library of Ireland. It will not help you if your folks were poor tenant farmers as it lists mostly Protestants, English and gentry, but is a treasure trove for the descendants of those who left these documents and pedigrees.
Go here http://www.nli.ie/en/heraldry-catalogues-and-databases.aspx and Scroll down to
“McAnlis – The Consolidated Index to the Records of the Genealogical Office”
Open the pdf for the chapter that includes the initial of the name of the family you are researching. Scroll down to find the name you seek.Print those pages.
Now go back to the front of that volume and read all the front material so you will know what this index is all about and print page 8-9 of the PDF. Those pages tell what the numbers mean so they will be an ongoing reference tool. They list MSS numbers of the Genealogical Office of National Library, cross-referenced to the film numbers at the FHL (VWM says SLC) (FHL film numbers now have 7 digits so you need to add a 0 at the front of most numbers.)
If you want to know if a film number of interest is at Bellevue, go here: http://bellevuewafhc.com/filmlisting.htm and look it up. If it is already there, you will save a lot of time and money. Many of these films are there because the Bellevue FHC is where Virginia spent all those years indexing these documents, although some of the films are at Port Angeles FHC where she later moved.