Thanks for the update. I’ll get those changes applied to my tool soon.
I agree, the shader, whilst brightening the image does appear to slow it down a little.
I think a lot of the definition of your sizing relates to you wanting the 4:3 ratio – would that relate to the “nostalgia look” mentioned here?
http://libretro.com/forums/showthread.php?t=1987&p=18368&viewfull=1#post18368
I quite like your TV overlay, so I keep that version with my setup :)
Also, I find there is a lot of variation in FBA roms, so I tend not to force the resolution there.