I'd only bother with WT+ on the Eastbound leg. It will presumably be an overnight flight and for me personally it's the difference between getting a reasonable sleep and no sleep at all. For a daytime flight the benefits are negligible.
Also bear in mind that in economy you will be able to put armrests up and your kids sleep with their heads on your laps (assuming they're at a suitable age). No chance of this in WT+.
Personally I would avoid AMS, but I am not a fan of that airport. Lengthy taxiing, lengthy walks. Language is no problem as the Dutch command of the English language is generally better than in England.