be careful with a softer saddle. too soft and you'll sink into it which puts your soft tissue in full contact with the saddle and bearing weight. you should bear most of your weight on your sitbones, which is really only possible with a medium to firm saddle. the absolute worst thing you can do is install one of those gel saddle covers. don't do it. get padded shorts-- buy MTB shorts if you don't want lycra-- and use a medium firm saddle at the least.
the thudbuster has a place but it's heavy. for any bumps of significance or any jump, you need to be out of the saddle to use your arms and legs as shock absorbers. this will greatly reduce pinch flats and bent rims if you hit potholes, also.