maximum .map size in mb?
is there a limit on tags/lines of script?

There is technically no limit on scripts and map files, but obviously the smaller and shorter the better your game will play on everyone's computer. If I made a game that my computer could just barely play, it would most likely not work on someone else's computer. So its good practice to keep that in mind as well as the polygon count on the models themselves.

'The Black Arts of Halo Mods' says "a general limit of 10,000 polygons is recommended (in one map file). This limit allows decent performance on most computers. In Halo terms, performance is measured in frames per second (FPS).

I think there's a dev command that will show FPS but I don't remember what it might be.

awesome, i plan on creating alot of content and script to stuff into a map.