Confused about ram compatibility

[50 Caliber]

Hello everyone. I'm planning on building this PC in October but i have a couple questions regarding the RAM. Here's the parts list:

AMD R5 1500x or 1600
MSI B350 PC MATE
G.SKILL AEGIS 1X8GB @3000MHz(F4-3000C16S-8GISB)
SEAGATE 1TB HDD
SANDISK SSDPLUS 120GB SSD
CORSAIR CX550M

I haven't decided on the case yet, and i'm planning on getting a used GTX 970 or a RX 570 if the prices go back to normal by then.

So i decided to go with a 1x8GB stick of 3000MHz since I've heard that Ryzen likes fast ram, and because I'm planning to upgrade to 16GB at some point in the future. In the motherboards manual it states this about memory (http://i.imgur.com/pIwRjXt.png) and in MSI's website, in the motherboard compatibility section, it says that it has support for the 16GB and 32GB kit of this particular ram, but not for the 8GB(http://i.imgur.com/jsyoQ51.png) that I want.

My question is should I get it anyway and get another 8GB stick in the future as i was planning to or are there going to be incompatibilities? Should i get a 2x4GB kit now and one later for quad channel or will it not be supported by the motherboard again since it states "Dual channel memory architecture". Feel free to suggest me other options that you think are better.

P.S. In my current system (H97 Gaming 3, HyperX Savage 2x4GB @1866mhz) I didn't select the memory from the compatibility list and it ran just fine @1600mhz because of no support for XMP.

 

[geofelt]

Ryzen seems to be picky about ram.
Go to a ram web site and access their ram selection app.
Enter your motherboard and you will get a list of supported kits.

You want support from a ram vendor in case of problems.

I suggest you buy your 2 x 8gb ram kit up front.
Dual channel ram will perform better.

Ram is sold in kits for a reason.
A motherboard must manage all the ram using the same specs of voltage, cas and speed.
Ram from the same vendor and part number can be made up of differing manufacturing components over time.
Some motherboards can be very sensitive to this.
That is why ram vendors will NOT support ram that is not bought in one kit.
Sometimes how ram is constructed becomes important to compatibility.
AMD seems more closely tied to ram than intel.