I don't worry about .pk3 size too much. A large map will frequently be 60 MB+ with bump and normal maps.
LCDLC Mapmaking Dept.
Maps finished: Hellhouse, Sorry, Worrior 1-20
Maps modded: CubeOrigin
Maps in release candidate: Blockforts, Cannons 1, Hotzone, Icecastle
Maps in beta: Arctica, Cannons 2, Cerulean-River, Igloo, Skygarden, Spacestation
Maps in alpha: Merlin, Totem