MacOS – 21″ Screencasting

I don't do a lot of LPs, but the last time I did I used QuickTime Player.app (Quicktime Player X); you'll find it in /Applications. To record your screen, select File > New Screen Recording.

The results were pretty good; recording Minecraft 1.7.3 gameplay on an about a year and a half old MBP, but I have a lot of RAM, so that certainly helps.

Edit:

It's worth noting that QuickTime Player X does not support loopback sound; meaning that the only sound recorded will be from the microphone, or virtual sound device providing loopback sound.

This may or may not be a good thing, depending on what you are doing.

It is impossible to deliver an "answer" to this question. You are asking for something that is purely opinion-based. I have friends who use super small fonts and it's very comfortable for them. I also have friends who use larger fonts, and that works best for them. I personally use a variety of font sizes depending on what Mac I am on and what App I'm using. Your best best is to work with whatever font size suits you, despite what anybody else tells you.

There is no "one-size-fits-all" answer to your question.