The only way you can really tell what your text and pictures look like is to check them on a proper television monitor.
Most computer monitors do not conform to the native sizes of tv pictures so things can look a little odd if say you are viewing a 720 x 576 or 1920×1080 picture on a screen that nativly displays 1680×1050
TV pictures will look better on some computer monitors and not so good on others depending on how much resizing is going on but usually there is some pixel mashing to make them fit your screen so sharp edges like text is the first to suffer.
You should get a good idea what your captions look like of you set your canvas window to 100% and make sure everything is rendered.
When you view them try to view them at native size if not you will find that 50% size looks better than some arbitary 65% size or whatever.
But for consistant results a monitor that can display native tv size pics will serve you best.
best wishes
Neil
http://www.patience.tv