Glad to hear that you are reaching breakthrough!
As for getting cheap, RCA in some of their models was a leader; they went downhill from 4 or 5 pix IF stages in the late '40s to a minimal 2 in some of their mid '50s B&W sets. I've even seen this pitiful minimum pix IF count in some of their
COLOR sets in the mid '60s.
Further to mention here that very few of their FM Hi-Fi sets used the Foster Seeley discriminator, but rather the ratio detector design, which has always proved inferior in performance as regards distortion figures, etc....
I've restored in the past a number of sets that employ the cheap 2-stage pix IF chain--including RCA models, but was never really satisfied with their performance. I suppose that if I at the time was a trained TV technician that I might've done better, but I strongly doubt it. I think that they were generally crummy sets meant for urban use only, and I never had lived in an urban area.
Now I've got a question for you: Have you ever seen any model of Zenith television set with any fewer than 3 pix IF stages....?