Chocobo Rankup - Research

So, for whatever reason, SE decided to make the chocobo ranking process somewhat opaque; the only representation we have of XP for our chocos is a gradually filling bar with no numerical representation. So, I created a little time to level widget for my chocobo that tells me what percentage he is through the level and how long I can expect to take for him to hit the next level based on the bar's process - far from exact science, but the best we've got.

I want to do some research onto the best way to level our chocobo - does it level faster on higher level characters who get more xp per kill, or does it level faster on low level characters who kill their respective mobs faster. Is it important to get xp chains? Etc.

First test:
Job: THM17
Targets: 18
Choco Rank: 4
XP Covered: 17.3%
TTL for entire LVL: 10HR55MIN

I noticed that when I have my Chocobo out that I see two xp gains listen in the chat. It will be something like Lancer Experience 250 (25% Bonus), but under that it will list Class experience 70. It only appears when I have my Chocobo out, so I assume it's the Chocobo's xp gain that's being listed.