Thanks all and, especially, Laura! I will be booking the smart fare in a 4 bed women's compartment.
I should have been more clear: "neither of the above" was not an option. : )
I took an overnight train in India from Jaipur to Udaipur with Intrepid and my 74 year old mother 1 1/2 years ago. It was fine even in 2nd class non-a/c. The multitudes of rats in the train station as we waited for the train just added to the experience! I expect Thello will be a step up; I will report if it's not!
Update: I booked the two berths in a 4 couchette compartment. English language website is totally buggy (hopefully, they know trains and train travel better):
1. The reservation page did not work as expected on my iPad. I was not able to book the 110€ fare. In between attempts, the 2 berth sleeper compartment Smart fare became unavailable. Panic set in.
2. It worked on my laptop and I got the fare, then my credit card didn't work. I tried it again as I dialed Visa customer service and the transaction then went through.
3. I was asked if I wanted a female only compartment. The options were "no" or "yes, with no additional fe". Say, what? I went with "yes . . ." We shall see.
4. The Terms and Conditions which one agrees to be bound by come up en français. While I could possibly get through them given enough time and a Petit Larousse, I didn't bother. My lawyer will kill me!
Thanks for your input.