Oh -- and I should mention one other thing -- if you are going to try for KLM Economy Comfort, go to KLM.com and buy the ticket there -- for whatever reason there is an annoying bug whereby if you buy a ticket on Delta.com for a KLM-operated flight, you can't buy Economy Comfort with KLM until check-in time for your flight, at which point the best Economy Comfort seats (or all of them) may all be taken. If you buy a KLM-operated flight on KLM.com you can secure Economy Comfort seats for a fee right now.