Here's what I did, I took my stock Falcon radiator to a local shop and had them re-core it. I inquired about a 3-row or 4-row and they showed me what I needed and I went with a 2-row.
You don't need to be concerned with how many rows your radiator has. Instead, you need to be concerned with how much surface area the actual tubes provide for the cooling fins. The more surface area, the greater the heat transfer, and the more efficient the radiator becomes.
That said, I have a 2-row, 2" thick core with more cooling efficiency than a 3 or 4 row stock style core. I wish I had a picture of the tubes, you could see what I mean. My radiator has 30% more tubes than a stock radiator and approximately 35% more mass for increased surface area. I do not have cooling problems and I'm running a 192 degree thermostat.
Mluck's original question centered around his car runing warm with an assumed 2-row and a 160 thermostat. The 2-row is probably gunked up a bit and not capable of maintaining 160, which IMO, is too cool for the engine anyway. I would suggest a thermostat in the neighborhood of 180 - 190 degrees with whatever radiator you choose. I think the 3-row will be more than adequate to do the job, assuming the rest of your cooling system is up to snuff. If not, you'll change the radiator and still have the same problem.