I realize this is a very subjective question, and I am looking for opinions on what everyone thinks is the best shader, or shader preset/combo.
Things like ScalenX I’ve tried and that’s pretty cool. I remember something called SuperEagle or the like I used to use as well years and years ago.
To be clear, I’m not looking to preserve visual fidelity at all, I just want the smoothest, softest looking image I can get.
Like… take an 8 pointed star and make it a circle kind of smooth lol
Scalefx followed by a pass of advanced-aa is very smooth. The old scalefx is smoother than the new one but not as “smart”. xbrz and xbr-mlv4-multipass (newly available for GLSL+slang!) are the next runners up.
ScaleFX. Add SharpSmoother or XSoft to taste if you’d like some blending.
Suddenly it all clicks, I should have been using ScaleFx this whole time… not Nx… Everything in that other thread makes so much more sense now.
Ended up using ScaleFx - hybrid - xsoft. This completes my shader preset project!!! 
Now I can happily cycle through.
No Shader > 0 - Handheld > 1 - RF > 2 - Composite > 3 - S-Video > 4 - Component > 5 - RGB > 6 - VGA > 7 - BVM > (and now) 8 - HDMI
Thanks for the input guys!