In forma pauperis only gets you out of having to pay the various court fees on your filing. It doesn't get you an attorney. As EJ points out, there's not going to be any court appointed attorney in a civil case. Such is provided federally only in cases where "life and liberty" are at stake. 43 USC 1983 is the section for civil action on civil rights issues.
What your attorney gets is a matter of negotiation between you and your attorney (in advance). If you have an attorney who's willing to take your case on a contingent fee (i.e., he takes a percentage of the results of the case. 33-40% is not atypical.
The 1983 action provides for you to recover fees attorney fees to reimburse YOU for your private legal costs. This is not predecated on your pauperis status. I'm not sure where the 24% is coming from, but that may be a cap on legal fees as a percentage of the award (note the fees awarded will be over and above your damage award). So if you sign with an attorney that binds them to 46%, you will have to pay anything over the awarded fees out of yoru damage amount.

