Rails and mod_ruby, performance, etc

Hi,

I've got used to Rails fairly well (though my question may not be the proof of this), and tried it with the following "platforms":

1, Webrick - nice, easy, but I'd stick with apache
2, CGI - slow, really slow
3, FastCGI - good performance, but a real resource eater

Now I'd like to try using mod_ruby, it is said to perform between CGI and FastCGI - I hope it eats much less memory.
I have a problem, though - I have no idea how to configure a rails app to work with mod_ruby. Apache is configured,
my test mod_ruby scripts work. Could someone please give some adivces, waypoints on this?

Thanks in advance,
Ochronus