Hello Stephen. I am also a lawyer, and I have also struggled with a reminder / task / delegation system. I have tried about ten different systems, but nothing (so far) has fit my needs. I am about to start a trial of Dooster. So far, it looks like exactly what I've been searching for. I am struggling a bit regarding how to best set it up, so I ran a few searches and stumbled upon your post.
Did you set up each matter/file as a separate project? What about administrative and non-client projects? It seems like the easiest way to organize it would be to have separate projects for everything, but that will push me into the highest priced plan. I'm fine with that if it gives me my sanity back, but I want to make sure there's not an easier, less expensive way to approach it.