Hello,
I don't know if the question is really about the formation but i would prefer talk about the animation. I mean, I can use 3 teams that mark their era by the offensive quality and that are still oftently shown as exemple, The 70's Ajax, The end 60's Brasil or even the Guardiola's Barca. The ajax was playing in 4-3-3, the Brasil in an hybrid 4-2-4 with four 10 in attack ( Rivellino - Tostao - Jairzihno - Pelé), the Guardiola's Barca with a reinvented 4-3-3 which was sometimes a 4-7-0.
All I want to say is that the tactics has to be made based on the qualities of the players you have in your squad, but the most important is how you will be able to make them play together and how they will be able to create movement and developed a football based on an offensive spirit.