All of our ukulele are inspected before they leave the factory, so no additional work on the action should be necessary. If anything, the player should adjust to the instrument. HA HA! Just playing around.
We set our action to a medium level, when they leave the shop. The string height at the 12th fret should be about .110".
If you do decide to adjust the action, it's easy enough to do it yourself, with a piece of sand paper. Sand the bottom of the saddle, so you don't have to mess with the angles at the top, where the strings sit. Keep in mind that you need to remove about double the desired distance at the saddle, to lower the 12th fret height. So, if the action is at .110" and you want to bring it down to .100", you will need to remove .020" from the saddle. This is about 2/3 of 1/32". A local guitar shop should be able to do it pretty easily. The nut adjustment will most likely not require and refiling.
As Chuck explained, higher action means more tension, means more volume, but harder to play. Lower action results in a sweeter tone, but not quite as loud, but easier to play. There is a limit to which the uke stops getting louder and just becomes difficult to play, with bad intonation. (As you go higher) I find it's about .120". Anything higher is just hard to play, the intonation goes sour, and you don't really gain any noticeable volume. There is also a limit to how low you can go. Below .090", most instruments will start to buzz, as there isn't enough clearance over the frets.
We happily adjust the action for free at our shop (no charge), but I understand we aren't a drive away from the mainland. If it's something you don't feel comfortable doing yourself, take it to a local luthier, or guitar shop. If you do decide to do it yourself, shoot me an e-mail with your address, and I'll mail you an extra saddle. That way, you can have one handy, in case you sand past the point of no return.
scooter,
It's hard to see clearly from the picture. If you have a ruler or gauge, the action should be close to .110". Personally, I prefer my action at .100", but our instruments end up all over the world, so we set them just a little higher to compensate for different climates. If the uke is hard to play, or starts to buzz on the frets, please shoot me us an e-mail and we will do our best to resolve it.