Well, I tested it out with RetroArch framerate being displayed and it runs at a solid 59.9 to 60.0 fps. This is also after I updated my /boot/config.txt to use sdram_freq=500

Still doesn't quite look as good as when shaders are disabled but I am thinking this is about as good as its going to get.

Edit: I also sacrificed the curvature and tweaked my overlay bezel art to push it as fast as it could go with at least the zfast_standard shader for both Waku Waku 7 and Samurai Shodown 4 (the only games I have installed that demonstrate this issue to my knowledge)