If you only have one readout the mast is problably the best bet for where to put it. We're pretty pleased with a readout mounted on each side in the cockpit.
We bought the wire extentions that are available from the KVH. First we (I) tried making our own extensions, got the pin connectors mixed up and let the smoke out of the control box. Net result, it cost a lot to have the control repaired. So much for trying to save money with a DYI.
