How I'm leveling DoH/DoL, suggestions?

So I've been doing the following for over a month now and I wanted to know if there was anything missing or anything I could be doing more efficiently especially when it comes to leveling up my DoL. I am doing my Ixali quests daily and using them for levels 15-40 on DoH and finishing them off with stockpiled delivery leves. I then go and use my rested exp on my DoLs in increments of 5 levels so they can share gear as I go up. If I have enough time I add in a GC scroll.

So far using this I've gotten ALC & CRP to 50, CUL to 40. I'm about to pop 22 leves on CUL to ding 50 and then do BSM. However, my DoLs are expectedly lagging at 20-26 each. I would really like to boost them a bit to 31 so my 3 retainers (1 BTN, MIN & FSH) can bring me crystals. But I can't use my leves on them as I'm using them for DoH obviously. Any suggestions on the process or free exp I'm missing?

Grand Company Supply and Provisioning helps a lot.
For the intended level, the xp reward is
1/8 of the level for normal quality non-starred items
2/8 of the level for high quality non-starred items
2/8 of the level for normal quality starred items
4/8 of the level for high quality starred items

Each craft and gather class have their own entry.

You can prove the items once/day, but they only accept items which is in the list for the current day.

When gathering, the only extra thing you can do is make sure you are going out of your way to collect items you haven't gathered yet. You get bonus xp everytime you gather an item for the first time. It might help a bit, but GC turn ins are about the only thing you can do extra besides that.