you also need to print this as well : http://www.thingiverse.com/thing:350649

makes the duct dead easy to install and remove as it just clips in.

Yep 24v 40mm fan as the board does not have any 12 v connectors.

I've wired up two now - both take the feed from the power from the motherboard's own cooling fan.
One I did with wire stripped from an old pc case and one with the wires wire from a network cable. Networking cable tends to have 8 strands of solid copper wire.

Run the wire round the case and up the bundled wire cable. Works a treat.
Mine are configured to be on all the time that the printer is on as I find it helps with all materials. But you could easily fit an on/off switch between fan wires and the power wires. I'm currently thinking about making one - when i find a proper conductive filament :-)