Hello,
I was introducing a new topic, but I see that we have the same problem! Could help knowing that you are not alone? This helps me!!
My DD will have 11 mo on the 15th of October. She started 1 mo ago to jump the afternoon nap, not everyday...sometimes. Now we are definitevely on 1 nap. I can say you how I understood that she was ready for 1 nap: when I managed to have two naps, she woked up very cranky from the second one and was impossible to put her to bed before 10.30 pm, crazy!
We have an A time of around 5 hs, in the morning she seems tired before, but if I try to put her to bed she resists and then jumps the afternoon nap. So I keep her awake till lunch, and put her down after lunch. Usually we have 2,5 hs nap, sometimes less (also 1,5 hs) but she resists the 2nd nap anyway. In this case I move the bed time forward.
Hoping this could help!!
Daniela.