I'm a single parent (full & sole custody). You said "single parenting + full time job + nights/weekends-style startup"... I mean I'm really, really not a helicopter parent; I have a life apart from raising my kid. That being said I think a single parent who's working full-time AND doing a "nights/weekends startup" would wind up short-changing SOMETHING.

I can't imagine there would be any satisfaction to be had in that kind of stretching.