How to level in Heavenward

[Zfz]

I just wanna chime in and say the duty roulettes are 100% not worth it. All three only reward as much as a heavenward dungeon's clear EXP for completion - and unless you get a heavensward dungeon out of the low level roulette (unlikely), you're missing out on the oodles of EXP the mobs in those dungeons give you (esp bosses).

Do you have some numbers? It would be interesting to check actual numbers.