21.5 or 23 for 1080p monitor?

I'm building a computer and I need a new monitor but I'm not sure if I should get a 21.5" or 23". Will text really be any smaller on a 21.5"?

I'll be doing only some mild gaming(minecraft, indie games). I'll also be working on 2D mobile game development.
I also experiment with 3D as well. I've made some 3D animations including things such as Minecraft and my own original series.

Also, 1 8gb stick or 2 4gb stick?

23" screen. Better for gaming and looks better.

Also 2x4GB sticks because you can take advantage of dual channel which is faster than just 1 stick