I'm wondering if anyone has tried using stride and stripe-width options when
creating an ext4 filesystem on a hardware RAID5 array.

Does it improve the performance of the array?

Should you create the filesystem directly on the partition?  What happens if
you create it on a logical volume that is created on the physical partition?

The LVM volume was created without options, ie, defaults.  I know LVM supports
stride and stripes as well but I dont know how they map to a physical RAID
device so I've never bothered with it.