[Erik Pagan] I work on an intel Mac Pro Tower with an HD flatscreen monitor (also from apple (definitely not what you descibed).
Since you’re not viewing your work on a broadcast monitor, you never can really see what you’re producing. Your output is always going to be hit or miss, hence the issues you’re describing.
To further complicate the issue, you’re using your own (presumably) consumer DVD player and consumer television to try to gauge what your final output looks like. And being that you’re getting wildly different quality FROM THE SAME DEVICE by simply swapping cables should tell you that your equipment isn’t doing you any favors.
You have absolutely no idea what DVD player, monitor or cabling people are going to use to view your footage, so the best you can do is shoot for the NTSC standard. Because that’s the standard that every DVD player and television manufacturer has in front of them when they design their equipment. It’s the only common denominator you have, so it’s the one you have to use. But the only way you can know what your footage looks like in the NTSC standard is to use a NTSC broadcast video card connected to a calibrated NTSC broadcast monitor.
Ever notice how DVD movies you rent or buy generally look pretty good no matter what DVD player or TV you play them on? Because the studios are all viewing their product using NTSC broadcast equipment calibrated to NTSC specs.
So if you really want to get it right, invest in a good broadcast card and monitor. If you don’t (or can’t) make that kind of investment, then just send what you have now. There’s not much you can do to make it right. Besides, you don’t have any way to know if you did.