The Dual is tricky because of the unique cartridge and carrier on the ULM arm. W/o the adapter, you're pretty much roped into that little ULM cart, and the standard adapters can go for $50+ easy...
Then again, maybe not. I'd have to get a better look at it to see if a standard cart can bolt up to it or not. It may be different that the ULM arm I had years ago.