FWIW, I use the phone patch in/out connectors on the back of my TS-520S for the digital modes and there's also a mod out there that lets you get the 520's output lower by applying a negative voltage to the ALC pin.

The only thing you need with my setup is a way to key the rig...  I just used the Send/Receive switch on the front...

I don't know much about the Argosy, but I use a TS-520 which has tube finals.  I've found that that radio drifts quite badly unless I let it warm about for about a hour or so before using it.

Hope that helps!

73!

Scott/W8CQD