Just an update. Luke Bellani of Star Stuff, a member of these forums, machined me a custom dovetail bar with a 4 inch wide platform and radius blocks to suit. He made the dovetail so I can use it as a saddle plate later on.
Now I'm happy with the way the OTA mounts, much better than the standard dovetail. Here are some pics:
Luke can be found at
http://www.starstuff.com.au/index.html
His work is just perfect! Costs: $215 Aust...cheaper than Losmandy and ADM saddle plate adapter setup.
All I have to do is learn how to use the Gotostar!