Wills probated in the Republic of Ireland, from 1858 to 1921, are on this site :
http://www.willcalendars.nationalarchives.ie/search/cwa/home.jsp
Thomas Richard Heaslip died 1905 is on that site. I also notice that there is a will for Richard Carson Heaslip in 1915, whose address was New South Wales. Presumably his son? You might be interested in that one too. (If Richard was in Australia but had a probate file in Ireland, it tells you he had assets in Ireland).
Irish wills from 1922 onwards are on this site:
http://www.cigo.ie/pages/guide-to-wills-and-administrations
They are indexed by date of probate so that can be a year or two after someone died.
A digital image is all you will need. The main document is the will (typically 1 to 3 pages), and I would suggest you must get it. You are unlikely to need the Grant of Representation. It’s the document in which the executor confirms that he/she has been named as executor in the will (or appointed as executor by the probate court), and undertakes to carry out the duties properly. He/she usually shows their relationship to the deceased (if any) and sometimes it contains marital information about the deceased, and information on any living dependents. The schedule of assets is what it says it is. A list with values of the deceased’s assets. Usually about 5 pages on a pre-printed form, needed for calculation of any estate duty (inheritance taxes). With low value estates (ie below the estate duty tax threshold) it sometimes doesn’t contain much eg house value £300, money in the bank £63 plus the cost of the funeral, and any debts. With a bigger estate, it sometimes goes into supplementary pages of detail about investments, land owned etc. There can be land valuation reports and statements of account from financial institutions. You’ll need to decide how interested you are in that.