It'd be difficult to estimate. Intelligence is valuable; even the most basic minimum wage job can be done better if you're more intelligent.* And then there's the schedule disruption - more than one polyphasic sleeper has cited that as a reason to go back to monophasic.

So you want to be someone with a flexible schedule & undemanding job. A good method for freelancers, I suppose, or students (eg. GPA correlates higher with 'conscientiousness' than IQ; consider http://medicalhypotheses.blogspot.com/2009/05/do-elite-us-colleges-choose-personality.html ); positions where consistency can be more valuable than peaks.

* claimed in Murray's infamous The Bell Curve; I have no particular reason to disblieve it