I agree it will be a build up of OT as well - but obviously you know whether you would be better throwing in a 2 nap day or not. I really didn't once I had started as Megan was just so much happier, and as I was ill it was just easier for everyone for everything to be the same every day.
It certainly took longer than a week for the OT to settle and the EWs to go. She had been EWing for MONTHS and I think there was an elemental of habit to it as well. We had given up trying to get her back to sleep at the EW ages ago as she just didn't and just wanted up - but we always left her to twitter for as long as we could as if we got her up the floorboards woke DS
. TBH we still hear her at about 5ish, but these days she goes back to sleep after just a few minutes.
I would say after 2 weeks the silly EWs had gone, and we were reliably getting 10.5hr nights. So at that point we moved bedtime back a bit to get a 6am wake-up - and that suited me fine as that is what we always did with DS as well. And then about 4 weeks or so after that she started sleeping longer.
So a mix of habit and OT driving EWs no doubt - but there was no other fix - and we were all happier with the 1 nap day - so we just stuck to it.
I guess what I am saying is don't expect the EWs to vanish any time soon
. But make your decision on the whole picture as her sleep habits will start to mature soon into that of a toddlers rather than a baby iyswim??