What are the easiest and hardest Primus songs to do on b?

I asked a question about starting a band somewhat of a time ago (It'd be helpful if you answered that too) and my band is thinking about being a Primus cover band. I like Primus and I play b. I can do Tommy the cat and John the fisherman, but that's it... so I'm gonna learn some more Primus songs, I need to know which are the easiest and which are the hardest. Can I get some help please?