Hi Carrie,
For what it's worth, here's my experience :
I too thought that Lena was far too young to transition and I wanted to hold on to 1 long nap + 1 catnap for as long as I could but it quickly resulted in Lena being too undertired to take a decent long nap AND she refused the catnap so we had a few days with only 45mins of daysleep
.
At daycare, they encouraged me to give the 1 nap a go and it worked like a charm, Lena is really surprising me in the amount of A-time she can handle, while still having great 12-13H nights (in fact, nights have never been better since we switched!)
We transitioned 3 weeks ago and Lena will still have the odd day where she will nap twice (mostly at daycare) but it is very very rare.
Our days look something like this:
6.30-7am : wake-up
11.30-12 : nap 2H (often 2H10 or 2H20mins), so wake-up between 2pm-2.20pm
6.30-6.45pm : bedtime
I would give it a go and keep a close look at Rory's tired signs and offer a catnap and/or early bedtime if needed.
It took Lena about a week to take this long a nap, it would be only 1H15 at first and on those days, we did a 6pm bedtime. I found that after a week, her bodyclock had adjusted to only sleeping once a day and that's when the loooong nap occured. (and this coming from a recovering 45 minute-napper)
I was scared as hell to try it, but it was so worth it.
Good luck!
Sophie x