Hello Ric,
Here in Brazil, repeaters in the 6 meter band have an offset of [500 kHz], almost the same for 2 meters, which is [600 kHz]. I would like to know why it is so difficult to find a duplexer for this band, while for 2 meters it is much easier? Do you have a link to the website of this group in Dallas that builds 6 meter duplexers?