Im not sure that the formation was that clear cut, you could even say that because of the movement of the team they didn't really have a fixed position. But I think the midfield 4 lined up as more of a rhombus shape than a diamond, so the 3-4-3 was sort of like a 3-2-2-3 formation. Bakero was placed more centrally as an AM/CM sometimes behind the main strikers with Laudrup playing more on the left AM sometimes as a pseudo winger cutting inside similar to how Iniesta plays. While Amor and Nadal ( Or Nadal as CB and Koeman as DM, maybe Amor as a cm) played a little deeper to support Guardiola as the deep playmaker.
Something like this:GK
" If I have seen a little further it is by standing on the shoulders of Giants." - Isaac Newton