I have the mens version of the Selle SMP TRK. I don't have problems really and always used the Fizik Vitesse but was having less time in the saddle and it just wasn't as comfy.
I bet other people have given you better advice and I don't know how this would work for you but it seems like this one wouldn't have much pressure on your tail bone.
Be forewarned, it's funky looking. If you ever watch Star Trek, it looks like a Bird of Prey. It works for me though, even in tri shorts.