I'd say that each kid is a little different. For my son (now 18 months) he will sleep a total of 13 or so hours ideally. Whether or not this actually happens is totally a day to day variation. He moved from 2 naps to 1 at about a year as well, and I found that I really needed to move the bed time up a lot while he got used to being awake for a good long stretch. I knew he was ready for the switch because putting him down for his morning nap became near impossible. So I watched his cues a little more carefully, and pushed that first nap back. Some times he would pass out in the afternoons around 4, and sometimes that meant that bed time was a little wonky (he would fall asleep closer to 9 or 10 sometimes, while his normal bed time is 8). Then he made a switch to being able to stay awake until 630, 7 pm, at which point he would be ready to "sleep" for the night. (I have a frequent waker, so he always woke up around his usual bedtime, but I was able to get him back to sleep without too much trouble). Then he slowly started pushing his bed time back to 8, which is his intuitive bedtime. This happened over the course of a month or so, and his 1 nap would vary in length, which would determine how the rest of the day went. It was really hard planning the day with just him, so I imagine that it will be harder with two around!
After that wonky couple of weeks I adjusted his morning nap time (slowly) to a time that worked better for us. So now he will go to sleep between 12 and 1230 most days and sleep for about two hours. Sometimes more, sometimes less. Never what I plan on (For night time sleep, he usually goes to bed around 8 and wakes up around 7).
Every kid's needs are going to be a little different; I would just look for DC's cues and try to follow as best you can. There will definitely be an adjustment period though.