Seeking a route from Glendine to "Stillbrook Hill", having summited Arderin, the map suggested that the Slieve Bloom Way offered a viable track leading to the open mountainside at Clear Lake.
And it does, but you're using an abandoned section of the Slieve Bloom Way (with a number of the old waymarkers still in situ, but many removed), probably due to some erosion having been caused on some parts by scrambler bikes.
Deviating from the track on the open mountainside leads onto spongy heather, even after a recent dry spell, quite difficult and tiring to traverse. And that's in June. Hence return by way of ascent.
I had learned of Clear Lake after a bit of google map perusing and reading of a route from the Baunreagh/Wolftrap side of the mountain in the book by John G O'Dwyer, who refers to Stillbrook Hill as "Dossaun Mountain". I was unable to find any references to such a name being used in historical maps, but I see that to the west of the mountain is Glendossaun, as marked on the 1:50k OS map.