Just read some research over the weekend saying, every-other row will give you the same results as every-row, with respect to nitrogen application.   The only time every-row application out-yields every-other row, is if there's not enough nitrogen for the corn crop.  So as long as we're giving our crop enough nitrogen, every-other row is fine.

Personally, I'm content with whatever equipment will get my nitrogen application covered up.  The cheapest, most efficient, and method of least maintenance for getting my nitrogen in the soil and covered up.... is good enough for me.  

"Too early" is kind of a tricky question.  There's no such thing as too early, if you never experience weather events that would diminish the availability of the nitrogen you apply to your corn crop.  But how often to you go through a crop year without getting at least a little unfavorable weather to "steal" some of your nitrogen?  Pretty rare.  At least for us on our farm we seem to always get at least a weather event or two that causes some nitrogen loss.  So we try to spread out our nitrogen applications during the growing season.  Ideally, I'd like to put on 40% at planting, 40% at V4 to V5, and 20% 10-14 days before silking.  That would be my ideal. 

Good luck with your decision, gordon