That's an awesome MB. Obviously you will want to connect your SSD's to the SATA Express port.
If you need more speed, then I would suggest you get more ram and make a ram drive. I won't go into how to use the ramdrive here, but ram is still way faster than the fastest SSD. I don't think it makes sense to use SSD drives in a RAID configuration unless it's a mission critical application that must not fail, and in that case, it is a RAID 1 configuration.
The regular hard drives, OTOH, can noticeably benefit from RAID 0.
Of course the best way to see what you want is to experiment, so definitely get some experience setting up raid. I have wondered myself if it was possible to use a smaller SSD drive just for the parity bit in a RAID 4 setup. But your MB only supports RAID 0, 1, 5 and 10 so you would need to experiment with that with a software RAID.