I have enough useful sight to use Numbers to work on spreadsheets is iOS and Mac OS with a mix of screen magnification and VoiceOver on iOS and speak selection on Mac Os. This works reasonably well for me although I sometimes get a little lost in the magnified screen.
I've been asked to help a friend with no useful sight to work on spreadsheets. Numbers with VoiceOver on iPad seems to be fully integrated in to VoiceOver, but I suspect that it will take a lot of practice and familiarity with the spreadsheet layout to work reliably and effectively this way.
I'd be interested in comments and advice from spreadsheet users with no useful sight who are totally dependent on VoiceOver either on iOS or Mac OS. Is this one of those tasks that it's probably best to leave to someone else or perhaps you're coping just fine?