How much quality is lost with the switch to 12 bit? I remember having problems capturing sound into a NLE using 12 bit. I was advised at the time to use 16 bit or higher. If I remember right, there was a way of correcting this in the capture process but I forget what it was. Maybe capture at 16 bit even though the recording was done 12 bit?
In any case another alternative is to use a better shotgun and a longer xlr cord and use the back ports.