Just an honest question: Would you, personally, take a case on contingency, that you knew you would have to put in an enormous amount of (non-billable) hours without any payout to you for perhaps 5 or so years????? Could you or your business exist that long? That is assuming you used all your skill and knowledge in determinning your client had a solid, substantial case.
I realize you might have other paying clients but if 50% of your time is spent on contingency???????????????????????