Had some time to look at these stamps.
First: the cover
Second: the 1998 and 1999 ISSP panes. The former has no phosphor frame, the latter has.
Third: ISSP and Questa (or at least, it should be)
The Questa stamps (pair on top) appear on a somewhat brighter white paper. Also, both have the same number of perforation holes horizontally. I make this just under 14.25 gauge. The 10.25 does not make much sense. I never heard of Questa using this gauge.
Vertically, the perforations line up. The 13.25 gauge also appears incorrect. 15 is closer to the mark. I am tempted to say the 2020 Hibernian is incorrect and the 2009 is correct.
I find the Questa perforation to be somewhat erratic. The ISSP one appears much more regular.
It appears the stamp at the top - that should be the 2001 stamp - has a wider setting of the word "Éire." Now, pictures can give incorrect images. I measure the original booklet stamp's inscription as 9 mm at the centre of the word "Éire." The booklet with phosphor frame has it 8.5 mm. And, surprisingly, the stamp on top - the Questa one - has it 8mm wide.
Well: the Questa stamp to the left is much duller under long-wave uv light than the ISSP one.