Hmm. Would you care to expand on this? I'm curious because I have an external VGA to composite/s-video/etc. converter on the way so I can play these games on one of my old CRT TVs.
It depends on the setup . For a standard VGA converter it shouldn't matter because the converter will happily accept the VGA signal and output as 480i to a TV.
I found that newer versions of Ootake couldn't switch to genuine 240p though, I had to go back to older ones (it works around 2.04).
However, the graphics card in my laptop is one of those that cannot output low resolutions like e.g. 256x240. The solution to this to simply increase the width (e.g. you can double to 512x240), and then the emulator stretches it appropriately.
Problem is, I couldn't find such a stretching option in Ootake, meaning it left me with a picture that's tall, but not wide enough.