John, please listen to the OP - he has a successful VHF setup already. Let's focus on what he wants.
pkw11, you are getting oustanding results with what you have - a modest-gain antenna trying to pick up signals that have scattered over a pretty tall obstruction. Click on any of the stations of interest in your TVFool report to pop up a path profile to see what I mean. Since you are happy with your VHF setup, let's try leaving it alone.
As a first step - try aiming the RCA up a few degrees. Although it does not discriminate much between above/below the horizon, tilting it up aims the maximum gain more towards where the signals are coming from out of the sky. I don't think you've going to get KSCI, but it's worth a shot.
What I think you will ultimately need is the big gun for UHF - an Antennas Direct 91XG. I'm suggesting this yagi-style versus a stacked bow-tie array because the 91XG will be sensitive over a bit broader range of angles of elevation than the bow-ties will. When installing the 91XG, definitely tilt it up a few degrees to put the peak gain more towards where the signals will be coming from. Its mounting bracket is specifically designed to do this. Combine that antenna's feed with your existing RCA antenna with a UVSJ device like
this to keep any UHF from the RCA from interfering with what you pull from the 91XG.