Eyefinity Monitor Sizes

So I have a 7950 on the way and I'm looking into Eyefinity. I have 1 Samsung P2350 (23in) and 1 Samsung P2770 (27in). They're both 1920x1080, so if I get another monitor with the same resolution I should be able to do the standard 5760x1080. My question is, what should I do about the 3rd monitor? The P2350's aren't being sold anymore. Luckily they're still producing 23in that look very similar to the old style, but they're all LED now. My older monitors are standard LCDs. Will having a LED monitor make it stand out compared to the others? Will I be able to calibrate them to look identical (something I would assume is critical for Eyefinity gaming)?

Also, has anyone tried a setup with 2x smaller and 1x larger monitors? Does it look weird? Are you happy with the way it works or does the size difference distract you? Is it not worth using Eyefinity unless all of the monitors are identical?

LED Monitor:
http://www.amazon.com/Samsung-S23A350H-23-Inch-Class-Mo...

My 23in LCD:
http://www.samsung.com/us/computer/monitors/LS23LRZKU2D...

My 27in LCD:
http://www.samsung.com/us/computer/monitors/LS27EFHKUF/...