If national airline offers unlimited contract then go for that. If not, always go for left seat as long as its on an Airbus / Boeing / large cabin bizjet.
Just remember one thing, there are very few good jobs left in Europe, where you would get a job as DEC, so when planning to "then move somewhere else" plan for that to be in Asia, or with a few exceptions perhaps in the ME. Unless of course you are ok with the €5500 and 7 days off per month that seems to be the new "standard package" in Europe.
CP