[old_tv_nut]

Another thing I didn't mention: if you use a baseband input (either S-video or composite) you will avoid the sound trap problems and get the full advantage of wideband chroma without the quadrature distortion caused by cutting off the upper Q sidebands. This will also give stronger I-axis color details, as you will be getting both I channel sidebands.

Some more theory:
To get full advantage of the I/Q system when going in via RF, the I channel should actually have a 6 dB boost of sideband frequencies below about 3.08 MHz (or the demodulated I baseband frequencies above 500 kHz) to make up for the missing upper sideband. Although this was discussed in some NTSC papers, I don't think it was implemented in any receivers.

Having full amplitude wideband I response also means that cross-color on composite video (the Johnny Carson plaid jacket problem) would be worse, but not on this set because it has a comb filter.