How do I know which one of my components has the best internal scaler and/or deinterlacer? Is there a simple test? Does my Avia disc have test that I could use?

I tend to believe that scaling the signal only once should be the best. Is this a valid assumption?

I have a 50" Pioneer Elite Pro-1010 plasma that is 1366 x 768 I think. I also have a SA 8300HD cable box and a Panasonic DMR-ES10 dvd player/recorder which can be progressive scan but doesn't upconvert.

I am thinking that the best way to pass the cable signal is "pass-through" and let the TV do all of the scaling. This scenario assumes that the Pioneer Elite TV has a better scaler than the SA 8300 cable box. This way, any signal, 480i/480p/720p/1080i will all be scaled once to 1366 x 768, the native format of the TV. Agree or Disagree?

Now on to the DVD player, should I send the TV 480i or 480p?

Please don't tell me to test it each way and see which one looks better. I tried that already and I couldn't tell much difference, but I also don't really know what to look for. I still want to know even if I can't tell a difference.:)

My TV has Pioneer Pure Cinema mode that I currently have disabled, but supposedly is helps with 24fps as long as you send it interlaced material.

Pioneer Elite Pro-1010