Hi Duncan,
No USB device may be controlled via the RRC, only serial devices.
Honestly, I think the RemoteRig may be overkill for what you are doing. You can use the Icom software
RS-BA1 to remote the 7300, since you would have to use software control anyway with the RRC. You can
remote the PC using Teamviewer and not have to worry about the rotor.
The only real advantage using RemoteRig would be good CW support, otherwise I think you can use a pure
software approach. I am a huge RemoteRig supporter, but not sure if it makes sense for you.
73,
Mitch DJ0QN / K7DX