er, yes?
1. the grooves are in the middle of each saddle, so flipping the saddle itself means the groove is still in the middle of the saddle.
Yes, but it would be on the other side of the intonation screw.
2. the saddles are already hard against each other, so there's no way to move the location of the upper saddles towards the lower ones. flipping the top two means trying to move the D saddle into space already partially occupied by the A saddle.
Moving the intonation screw will help mitigate that. If what you fear may happen should happen then other measures may be necessary such as filing a new groove or trimming the saddles. Maybe even drilling new holes for the intonation screws and or the strings. Why not? It's easy. At least the bass would be functional.
3. the lower saddles are already flipped in that direction, there's no way to move them any more "bass-ward". (even if you could, that would just mean the E string missing the neck instead of the G)
I never said anything about the E or A string saddles, but you can work on those too if you want.
please tell me which of these statements is wrong and how?