I have been to the National library of Ireland twice in the last few years. You just need to pick up a "readers ticket" at a desk downstairs. They have some volunteers on hand in a special room to right as you ascend the stairs to the reading room to help with where to start etc but it has facilitated my research to know exactly what I wanted before I went rather than wait for a volunteer to help me. I brought a list of the microfilms I wanted and had the numbers ready to fill out the request cards at the desk. The library has a website that explains all this (google National Library of Ireland) It also has an index on line of microfilmed church records and the years their records cover. (you will need to know the diocese) Doing your homework before you leave will help a lot! I never had problems getting films or a reader to do the research - but discovered that rainy days get more crowded than nice ones. The real problem might be that records are hard to read so it takes longer to go through some registers. They have magnifying glasses at the desk that you can borrow but even that sometimes doesn't help! You are limited to requesting only a few films at a time but the staff are usually swift at retreiving them and delivering them to your film reader. Last time I was there they had a little cafe opened on the first floor and gave those with a reader's ticket a 10% discount not sure if that is still true but it saved time finding a place to eat and getting back to do research. There is a hotel across the street with a pub that serves lunch. Good luck!