Which saves more space?

I use the names of decks in couple of thousand cards through css code. For that I have quite a few decks to segregate chapterwise. After I first study the cards, I don’t necessarily need multiple decks and can combine cards in a parent deck. But I still want the deck name.

Can you tell which one of the following options uses the least amount of space (since anki has a 250mb limit) -

  1. Keep using my current deck approach.
  2. Individually add the deck name to add the cards (would the text on so many cards take too much space?)
  3. Add tags and follow the option 1 approach.

Please advice if there is an even more space efficient way than the above options.

Also, do having more decks consume more space?

The least file size taken would be option 1, as only the deck ID property of the card is used in the database. No content is being added to the database for the cards (notes in reality). You only get the CSS once for each template you use (card types within the same note type).

Yes, decks take more space but it is negligible, it won’t be a reason to worry about hitting the 250mb limit.