Although you do get these options in the help text (ie. when you do enter
gdialog without any option), gdialog doesn't use <height> and <width>.
gdialog --yesno hello 10 10
gdialog --yesno hello 10000 10000
do exactly the same thing.
Gdialog accepts options dialog does so that you can use files without
conversion. It doesnt however honour all of them. Its not even clear how it
should in some cases