Personally, I always prefer the translations as separate posts. Many try the stacking method like you did here. It can work, but as you said with longer posts it can cause other issues. Some try to put the translation side by side. To me that method is just plain annoying as it makes the room each text gets way too small, and that is with two languages.

For your posts, which we know go a bit more in depth I would definitely suggest keeping them as separate for each language. It will keep things cleaner that way. The titles will stand out more as well to those reading each language.

From a Curie standpoint our only concern is that the translation is done in a relatively short timespan and that it isn't just a simple Google Translate. For Curie purposes you should always try to post the English version within a few hours of the original languages. I might even suggest you write it in each of the languages and then post them all at the same time one after the other.

I do think that if someone is doing just a Google Translate in three different languages is when it becomes "spammy". Because really if you post it in Spanish and I want to read it for some reason, I can do my own Google Translate of it. No need for you to make a second post doing nothing more than copying and pasting what Google says and then earning rewards on it.

If you are actually taking the time that you do to translate it and then make it all make sense in English and German then THAT is a valuable service to the community and deserves whatever rewards come from it.

So there is my opinion. Hope it helps.
Gene