I also vote to leave the default at 3 for both.
Although English has a lot of two-letter prefixes, it's considered bad form to hyphenate a word leaving fewer than three letters (either the first or last in a word) on a line (according to the Oxford Guide to Style at any rate). IIRC a similar three-letter style rule also applies in Dutch and French.
Thank you so much again, ixtab! And happy new year!