I can't help but to think that you are leaving something out or we are missing something here... I've read your other posts about this issue and what you are saying doesn't quite add up.
So, let's talk about the basics...
I'm assuming you are using two microphones and are trying to make a stereo recording of a live performance. That is what the majority of folks here are doing.
So, one microphone goes into the right channel and the other goes into the left channel. Each mic has it's own channel. Your recorder makes a stereo (2 channel file) with one mic on one channel and the other mic on the second channel. Unless you want to blend the two mics together there is no need for panning.
Even if you want to level match the two channels, you would just raise or lower the volume on the individual channels.
Can you explain in more detail what you want to achieve?
I think the answer to my question is the marantz records to stereo automatically... though i guess there isn't a way to adjust the width of the stereo image?
Ah, OK, that makes more sense!
You get the stereo image by the way you set-up your microphones. If you pan together two tracks you can collapse the stereo image, but you can't really make it wider after the fact. I know there are some DAW plug-ins that claim to do that, but I haven't heard one yet that works better than using proper micing technique from the start.
Some advanced techniques like mid-side recording allow you to adjust the width of a recording after the fact.
That would be something you can look into.
There is plenty of information about that here if you do a search.