Thanks for this! The reverse LPF has greatly improved my 2-chip SNES image in optimised mode. I initially had the issue with bright pixels when using too much reverse LPF. I found I needed to make the following tweaks:
Video LPF: Off
Analog sync LPF: 10Mhz
Analog sync Vth: 45mV
I’m guessing that these settings effectively move the horizontal sampling offset slightly in optimised mode. It’s enough that Reverse LPF setting of 3 can eliminate the effect almost completely, for my SNES at least.