I use a tv tuner card or a TV

fact is if its composite its pretty much going to suck, if you have a monitor (ie high rez vs crap tv) it will be better (at mono) , but still

one of the projects on the books is to tap into the // series video generation circuit

but its currently at # 5 (so dont go holding your breath) otherwise have fun!

(the good thing about the IIc series is that the "rgb" port that exports every single signal except for rgb has a pin for serial data that is the pixel dot clock in a nice ttl format, sans color of course)