Screen Capture 10.0 vs 10.3

I'm trying to capture a section of the screen at the best quality I can, but there are problems and I'd like to know if what I have found out is correct:

Using Quicktime 10.0 under OSX 10.6.8

1. I cannot set the area of the screen to capture, but I can alter the video quality to either Medium of High.

2. Medium quality actually gives better results but results in larger file sizes.

Using Quicktime 10.3 under OSX 10.9

So that I could set the screen area, I booted into OSX 10.9. However, I cannot change the video quality.

What OSX and QT version do I need to be able to adjust the screen area and the video quality?