i used a single large condenser microphone to capture a rainstick for a song i produced for a band called "Kettlefish"..
i posted lengthy reports and posts here..
anyway, i blended the sound of the rainstick, with actual rain samples..
worked great.
the rain is, of course, very organic, and the rainstick is very, well, in your face....
distance from the mic helps, with a rainstick, unless you are going to do what i did, use 'elements' of it in a mix, rather than feature it in the mix...
the choice of mic is key, otherwise you could end up with a sibelent mess when mixing.....