You can mix ETTL and Manual in any group as well as ETTL ratios in any groups.IMAGE LINK: http://www.flickr.com …/15168416@N00/6375767913/
I would forget the old Canon style ratio screen altogether! (even Canon has moved on with the ST-E3) The Nikon style interface where you can adjust each group FEC (or manual) all displayed at the same time is the the whole point of the Odin.
To set a ratio all you do is set the groups to ETTL and adjust the FEC up and down for each group.
You can then set group C to a ration that way as well, or a manual power level (image left). (Image right is the old ration screen - kill it! )
Adjusting FEC on the camera then adjusts all ETTL groups up an down globally.
Adjusting FEC set for more than one group on the TCU is how you create the ratio. Having a fill light one stop down from the main light for example (image left above) makes a lot more sense than a meaningless ratio on the old system.
And you can quickly set any group to manual then if needed too, thats why the Odin is so much better than the current Canon system. You need the 5DIII and ST-E3/600EX to do that otherwise (or PW TT5/AC3).