So i'm doing my own experiment here to see what i get by feeding my chocobo, berries until i get one "new feather" proc. I'm hoping to get corpse blue at some point.
First 6hr feed:
Starting colour: Desert yellow (R:215 G:183 B:87)
3 berries fed at 1 minute intervals, got the message after the 3rd berry.
Colour result after 6 hours: Ul brown (R:183 G:167 B:119).
That means, if current theories are correct about RGB, then these berries increased/decreased the RGB values as such; -32 red, -16 green, +32 blue.
Second 6hr feed:
Starting colour: UL brown (R:183 G:167 B:119)
4 berries - 2nd and 3rd fed in quick succession (no proc), waited 1 minute before feeding the 4th, got the proc.
Colour result after 6 hours: Gobbiebag brown
Third 6hr feed:
Starting colour: Gobbiebag brown (R:191 G:167 B:135)
2 berries, fed 1 minute apart - proc'd after fed the second.
Colour result after 6 hours: Shale brown
Fourth 6hr feed:
Starting colour: Shale brown (R:151 G:135 B:111)
2 berries, fed 1 minute apart - proc'd after fed the second.
Colour result after 6 hours: Goobbue grey
Fifth 6hr feed:
Starting colour: Goobbue grey (R:135 G:135 B:135)
2 berries, fed 1 minute apart - proc'd after feeding second berry.
Colour result after 6hours: Lavender purple
Sixth 6hr feed:
Starting colour: Lavender purple
6 plums, fed one minute apart - proc'd after 6th plum
Colour result after 6 hours: Corpse blue *bah bah bah baaaah-bah-bah bah-ba-baaaah*
/joy /happy /cheer
EDIT: Not sure the RGB thing is a thing, so hidden this bit but left it available for others to speculate!
So, if current theories are correct, and colour changes only occur by how many times you get the "new feather" message, then according to the result above for the first feed, the one feather proc i received in feed 2 should give roughly the same values - giving me approximately R:151, G:151, B:151 (which is really close to corpse blue [R:151, G:151, B:167]). Fingers crossed anyway...
I don't hold much hope though as an fc member fed 5 berries, with 3 procs for his first 6hr feed, leading to UL brown from desert yellow. His second 6hr feed was 17 berries (he didn't tell me the procs but he thinks they happened alot after the 3rd berry) and he got Othard blue (R:55 G:87 B:135). As you can see, these values are strange when compared to UL brown. Berries are supposed to deepen blue hues but according to the math, the blue value only went up by +16, where as the red value decreased by -128.
Getting more and more confused...