I agree that silvermoon chest is best, I'm currently farming a perfect version for my hunter. I've gotten quickblade 6/5 and aurora 6/6, rip me.
https://www.wowhead.com/item=23409/well-crafted-long-bow&bonus=3639 from ghostlands scales to 16 agi if you prefer that over what you have, but personally I think the 11/11 is better especially if you solo queue mostly. (the blue bow from the end of ghostlands also scales to 11/11 when proc'd epic, I know that's not really relevant to you, but good to note)
Also, since you can use agi leg armors without exploiting onto boe pants, I would recommend you farm
https://www.wowhead.com/item=2166/foremans-leggings With armor kit, you still get some secondaries and the amount of agi you get would outweigh the secondaries on boa. I think I'm gonna hold off on farming the chest to farm these, because I 100% believe epic Foreman's is bis.
Also here's my hunter for reference:
loops brother Ignore my severely outdated gloves, trying to get better ones, but this set is kinda the direction I'm going for. I'm using argus rings because they're technically max agi if you're like me and have had such poor luck with quests, but I still think 1 bg ring with some secondaries is bis. (I don't have enchants for mine, so I have to hold off on that.)
I'm also working on farming the agi boa trinket, luckily my accounts are merged so it'll carry over without me needing a sub.