Dual M2's is a great setup for raid. If performance is what you want then just make sure you get the following. M.2, PCIe x4, NVMe. Also, make sure they're the same size. The Samsung 950 Pro's are great for this kind of thing btw.
Now, one thing to keep in mind doing this. Dual PCIe M.2 in Raid is gonna be the most grabby of the motherboard resources. On the PCIe side of things, you'll lose the PCIEX4 PCIe x16 slot. That 4 channel slot will be used for the M2H_32G port. On the SATA side of things you'll pretty much lose the use of everything except SATA3_4, 6 and 7 as well as all of the SATAe ports. So keep that in mind if you'd rather have mass storage over super boot drives.
Anyway, good luck.