1. The main screen is usually where you want your attention. The more info you can put on your main about your slaves without hindering your view the better.
2. Alot of us use things like clickboxer or click area and a mouse broadcast so using these addons is the same on our main as our healer. Like I use healbot on my main as click thru then i have hotkeynet broadcast the mouse click over to my healers window to press the same area. It works about 95% of the time. It's rare due to screen size and ratio's that I miss click.
3. Using pip Fraps doesn't always recognize you changing to one of your alts screens. It will just continue to record the main screen so you don't get to see whats happening in the background.

Regarding the jamba follow it depends on how much lag your system gets. Alot of times due to the main's screen size it has a little more video lag than your alts. If you look at your alts on the smaller screen size thats usually a better indicator of how far back they are.

Edit: Lol holy crap Ualaa. You beat me to it hahaha