Looks interesting!
Only issue I can see is that you are limited in size if the map is linear, have you tried compiling a simple map with the maximum length (turn off everything except the basic compile options) and seeing how long it takes to cross?
Of course, you could use height to extend...
just copy the map to the cs source folder after you have made it, I made a nice little batch to do this for me, you could also change the default directory to place maps in for each hammer setup.
check the output of the console when you compile the map, you may have an error which is stopping...
brushes/blocks must be convex - from any point inside the brush you must be able to see any other point without crossing the surface.
you've made a concave hull which is not acceptable, it should be broken in two (either through clip or by creating a new brush)
I'm sure I read about something for mp which redirects people who try to download so that they download the map from a http server rather than the game server, can't remember where through.
try to create a complex room using hollow, then add several entrances/exits. its nasty.
hollow should be banned, when I first started mapping I tried to use it, and it resulted in a lot of headaches, when I realised I could just create all brushes from scratch mapping became much easier...