This also has been discussed several times over the last year, search for those threads. I tried exactly what you intend, I found my rates (as determined by the "How to be a Consultant" books) was too high and unrealistic. This translated into "no work".
I developed a graduated scale based on type of work, percentage of total work that each type would encompass, etc. Good luck, every 1st time solo has to go through this learning curve.
TygerDawg