I'm pretty comfortable when it comes to spraying over the top of corn and have done so for the past 15 years without too much excitement.  With all the rain we've had the recently I was not able to get all my corn cultivated/ridged.  The fields will be fine but my end rows are going to be a mess so I'll need to spray them in the near future.  The corn will too tall to get through the canopy so I know I'll need to use drops.  I expect I'll using some combination of glyphosate, dicamba, and acetechlor.  What are the "rules" when using drops?  Is this relatively save as long as I keep it out of the whorl?