Hey Yorgaki1,
let's take them one at a time:
"Can I only record the channels I use?" - yes, you can, but it will require a bit of fiddling... In MasterFader, you can only set the number of channels to record, starting with 1. BUT: what you can do is: change the USB output patching! When recording, the DL32R will record the channels USB1 to USB32 (or less, depending how you set your channel count for recording). So if you use the USB patching page to set Input 9 to USB1, Input 10 to USB2, Input 17 to USB3 etc, you'll have everything set to only record the relevant channels. Fortunately, USB patching is saved with your snapshots. So go and save your existing mixer setup in a snapshot, create a new "Trio" snapshot and then change the USB output routing. Now save this "Trio" snapshot. All done - you can now record exactly the number of inputs you use.
"Can I record a stereo mix of the main outputs at the same time" - yes, using the same technique outlined above. You can patch the Main Out stereo pair to a pair of USB outputs and record them. I'd recommend you use the first pair (USB 1/USB 2 ) for this and then consecutively assign your other used channels to the rest of the USB outputs to keep things simple - no need to move them if you should add more active channels. Plus an additional benefit - see below.
"Can I record only a stereo mix" - yes, same technique as above. Using my approach of keeping the stereo mix assigned to USB1/2, you don't even need to change the patching - simply set the number of recording channels to 2. This will only record the stereo mix and ignore the other channels you've set up on USB3,4,...
Hope this helps!
Cheers,
Torsten
