I fly this route quite often. I am a KLM Gold elite and i dont really get good service from the check in staff at Delhi!! Infact I have just given up on them, must be the rudest check in staff in the world!

They will just laugh at your CO card, so dont expect anything from them on the way back.

They never do Elite boarding either at Delhi airport. Its just a rush to see who can get in the airplane first even though we all have seat numbers.

In regards to your seat, since you will be checking in some 10 hrs before any of the European KLM customers i think you can preety well pick what seat you want. Or you can always ask the staff at the lounge when you in AMS to see if they can give you a better seat as they always have seats held back.