SNM:
I really, really, really don't want to imagine myself as that balding, pasty, pot-bellied loser...
Only the balding, pasty pot-bellied winner! Seriously, there is a sub-set of spanking fantasy which precisely makes the men as unattractive (superficially, at least) as possible. Early Januses (I think) featured stories about a dedicated spanker who was short, fat, bald, bespectacled, with rather heavy, pudgy facial features: I think Hardcastle illustrated him. I suppose this increases the humiliation quotient.
What's wrong with big men, by the way? Apart from Arnold Schwarzenegger's acting talent?
In general I'm not attracted, in fantasy or fact, to fat women, though a huge bottom on a woman not generally fat can turn me on, and she cazn be just a bit plump. An older woman with a big, floppy bottom does not light my fires, though I suppose it would be quite amusing to have Angela Merkel spanked.