I have implemented partitioning xfs and btrfs disks in UD to match the setting of Settings->Disk Settings->Default Partition Format. The partition will start at sector 63 or 64 based on that setting. This should allow disks formatted and partitioned with UD to properly go into the array.
With the release of 6.4.0-rc8q and the change to be compatible with 4Kn disks, there seem to be more issues with disks formatted with UD and put into the array. I had to change out my cache disk on rc7 and unRAID would not format it. I formatted the new cache disk with UD and installed it as my new cache disk. unRAID accepted the disk and went happily on its way. When I upgraded to rc8, the cache disk became un-mountable. I would have thought that the original formatted cache disk starting at sector 2048 would be rejected by unRAID and force me to format it. It did not and accepted that format. I'm seeing others that have upgraded that are probably having the same problem.
Please consider this feature beta until it can be tested beyond what I could do with my limited supply of disks. For those of you with a tolerance to possibly having problems, please check it out for me and provide feedback. I'm not an expert on unRAID disk formatting and partitioning, but I think what I did will accomplish the job.
Note: I reluctantly put the time into this feature because of the issues that have come up and I don't see LT folding UD into unRAID in this release. Hopefully this is all that is needed.