use RGB32 for galpani2, it has blending, very evident in the videos available.
I also wonder if the rgb15 layer is 256 pixels stretched to the same size as 320 pixels, the data written during the RAM test compared to what is shown on YouTube videos is suggestive of that.

I guess I should try and find the gal images in the data roms to see what format they're stored in too.

no real improvement, just the result of me studying it for a bit (nw)