Here you say that the max size for desktoip HTML5 is 2560.
https://krpano.com/docu/xml/#display.hardwarelimit
However that is not quite true. From my tests it is still 2200.
If you make multiresolution with for example 2 levels 1260 and 2520 it only loads the 1260 in HTML5 Safari.
You do not have that in the dokumentation so most people will believe it is the 2560 even if I can see that if you read more about you may mean that this is the max size if you use the extra option with adding hardwarelimit.
But that does not make sense as you say 1024 for iPad and you do not need the hardwarelimit for that.
Hans