If all you are changing is worldspawn keys, it seems like you just need to create ent files rather than recompiling all the bsps. That would take less space.

In terms of whether you can legally distribute recompiled bsps, check the license that came with the map files. 

I made .ent files with added "fog" and _liquidsalpha values but it does not affected on QSS so I had to recompile sources.
Yes I read terms of conditions in readme and I doubt if I'm have right to put it here if it have restriction "may NOT be modified IN
ANY WAY". By the other hand I just put together official "A" and official "B".