I picked up on radiant pretty smoothly, within an half hour or so, but now in SVG editors I keep hitting the space bar to copy stuff.

I guess the reason why I haven't actually released any maps I'm working on yet is because I need to figure out a better layout. So I'd try drawing some maps out on paper first, then pop them into radiant. Mapping will be much smoother that way.
if you have radiant 1.5.0 installed the first thing you need is the nexuiz.game plugin. I have this on my desktop, but I'm at school right now and my desktop is not on, so after 3:00 PMish EST (when I get home) download this:
http://server.stormassault.com:8080/sha ... z.game.zip
I'm shutting my desktop off at around 8:00PM EST because I'm going away this weekend.
Just unzip that to you're radiant installation directory and you've got nexuiz support. Look around for mapping tutorials if you really have no clue on what to do.