I hope a screen shot of the email or a download saved to a phone from the site works because if you have to PRINT out the email it's hardly going to be a "digital" entry 😛
you're really asking people "how much space does a 'yearly extension of stay' take up?', <- that isn't a "retirement visa", it isn't a visa at all, it's exactly what the stamp in your passport says, a yearly extension of stay
well IF you didn't let this last one lapse <- (meaning you'd start all over from zero 😮 ) and are just applying for a new year extension it's a half page
hardly took up an 'ungodly amount of pages' 😛 I sense some hyperbole 😉
to go from a free stamp to 90 day Non-O and then a year extension usually takes THREE total pages, the Non-O visa, the 90 day stamp FROM the Non-O (which some offices put on it's own page) and then a half page for the year extension.
Now that you have an extension just getting a new one only takes a half page stamp for the year extension and then another half page stamp for the re-entry permit (if they orient it side ways on the same page as your extension