Here a thin early stand will almost always out yield a full later stand.  This is assuming it's unevenly thin.  4-5 ft gaps and drownouts would be questionable.  Personally, I have never had late planted corn outyield an early planted.  Early for us is before May 1st and late is after the 15th.  I'd never consider planting corn after June 1 here unless it's spot replanting.

One factor you didn't mention, which is a big deal for us northern guys, is harvest moisture and even the potential for a normal fall frost (sept 15th).  I've had the pleasure of replanting drownout spots twice in early June.  Even cutting back the maturity 5 days was not enough.  The corn yield was well over 30 bushels less and more importantly, 30% moisture vs 18% on the rest.  Drying 15 points is miserably slow in October here and expensive. 

Frosted corn doesn't dry easily and is light.  But I'll leave test weight out of this discussion :) 

If you are down south that may or may not be the case.  But here I start to get jittery if we don't have the corn in by mid May.