Cas latency - which one to get and why?

I'd like to buy 16GB of RAM, but I am not so sure if I should pay more for CL12 if CL16 is fine @ 2400Mhz.

I'd buy two sticks of this:
https://www.pcx.hu/kingmax-8gb-ddr4-2400mhz-memoria-051313

Or a kit of this:
https://www.pcx.hu/kingston-hyperx-savage-2x8gb-ddr4-2400mhz-hx424c12sb2k2-16-memoria-931726

I am trying to cut a bit from the cost. Here is the build:
https://pcpartpicker.com/list/XNydTH

Initial choice for motherboard is the Tomahawk. Now...

Cas latency - which one to get and why?