It sounds like the level editor might be a better option for you given that the levels are the size they are - you could load different maps given the situation, allowing for better memory management.
If you want to use the actual collision functionality, you will have to use the sprite commands in your game as opposed to the drawSheet()method. This allows for the sprites to interact with the map collision data - but it also means that you must change a few other things too. Commands like setSpriteAnimation() and the sprite camera system are all made for use with the map editor.
I'll send you a dm becasue there's more to go into here and I forgot to respond!