I did a doc last year, pre version 10.0.6, with around 800GB of material, some from XDCAM, some from DSLR and even from smaller digital camers.
My setup is different: 2012 iMac, 32GB RAM, Pegasus 12TB Tbolt RAID.
FCPX handled the project quite gracefully, if you except the times when it would hang when I was frantically looking for a shot, skimming quickly from one clip to another. may have happened 10-15 times over two months.
Other than that it never lost anything, even when the whole setup lost power because of a short caused by faulty air conditionning.
I am with Mathieu here regarding RAM, I’d fill it up to the gills.
Let us know how it goes
Patrice