George, much will depend on your forage and length of flow, your willingness to feed, your winter conditions, etc. And raising your own queens, or having the nucs spend time raising them will also cut down on production.
If you are going to maintain the original colonies and just make nucs, I would suggest taking three frames from each colony and replacing the frames with foundation, every three weeks for as long as you can and a flow is still happening. You will maintain the full size colony and they will quickly fillout the new frames, and you can use the three frames you pulled to start nucs.Playing it safe and not knowing all your factors for your area, I'd say you should end up with as minimum of 2 full hives and 6 nucs, or if your really aggressive, two hives and 12 nucs.
You can also take the full size hives and just break them apart all at once in the beginning of the season. So you could start with about 14 splits and just let them all build up during the flow into strong nucs or even hives in an ideal situation.
I'd start aggressive early, and then combine midsummer if you know hey will not build enough on their own. Just do not wait to long to realize this. Combine early and don't think the bees will work miracles.