After obtaining 99 please be aware that up to I believe 30m EXP is stored at 99 Champion. Meaning when you job change to sura and kill 2-3 mobs you level instantly it helps alot, so be sure to grind a bit as a champ at 99/70.
Since the last update, I recommend against this now. Been using the guide as pointers so far to base 101 but now the games a bit different it no longer applies.
They added some new permanent kill quests from Eden that are for level 90-99 only, and they give a decent amount of JEXP as a reward to help balance trans chars who seem to hit 99 and still be lagging on JLs.
The point is this:
You want to hit 99/70 with as little stored exp as possible. Then go to Sura and still be 99 base with a lot more to go until 100. Pick up the Eden quests (I prefer Roween, Stapo, Heater, Freezer, Soldier and Siroma). Do them all at once and then do the turn in with a 3x and JEXP manual active.. you get many job levels faster which is nice to unlock the 3rd class skills faster. I was able to make it to Job 11 before I dinged base 100 and I think I was only 50% away when I first became Sura. Now I'm sitting at 101/12 and I must say the instant 11 job levels was really nice to get SB maxxed and a bit more instantly
The Eden quests only have a 3 hour timer. I think I only had done about 2 rounds of them honestly, so it's about 2 hours worth of work and a 3 hour cool-down in between to get all of this.