The Reining Champion

To do The Reining Champion you have to first ride the horse [npc=127718] at 51.51 26.25 Norwington Estate stables. Then talk to [npc=124802] to score your next run.
After that step into the arena with barrels and fences to start the achievement.
You'll have 3 abilities:
[spell=252847] - speed boost.
[spell=253030] - spear attack in fron of you.
[spell=253494] - throw bolas at zeppelin
For each killed barrel with gnoll you'll get 1 point, [npc=127708] - 50 points.
When you jump the fence you'll get a stacking 5 sec buff [spell=253498] which increases points gained after a kill by 1, maximum stacks - 100.
For now you have 60 seconds to do the achievement.
Important part is to shoot 3 zeppelins, you'll hear when they come out when [npc=124802] yells "Zeppelin out!".
You'll only have a couple of seconds to kill the third zeppelin before the time runs out.
Make a macro:

/target Paper
/click OverrideActionBarButton3

so you don't have to click on zeppelin. (You can put macros on any secondary panel, only the main panel spells are replaced. Secondary panels are hidden when you are in the vehicle but the macros bindings still work.)

Strategy that worked for me to get 600 points:
Enter the arena from the east side of Norwington Estate.
Follow the loop of 6 fences which form a circle path, leave the 2 fences on the other side of the arena, you don't need them.
Make the first loop without hitting gnolls to accumulate [spell=253498] stacks (7-10).
Then include gnolls in your rotation, they should respawn when you come back for another circle run.
And don't forget to shoot zeppelins.

/way Tiragarde Sound 51.51 26.25 [npc=127718]
/way Tiragarde Sound 51.60 27.16 [npc=124802]

The Reining Champion video: https://www.youtube.com/watch?v=qmx86TG_DMk
How to setup macros: https://www.youtube.com/watch?v=zGLnBRv-9cI

This is such an horrendously irritating achievement. I thought it would be fun, but the mini-game is extremely buggy. The majority of your jumps don't even register, the hitboxes on the gnoll targets is ridiculously small (making you miss half the time) and the timer is -way- too low. 98% of the time, the NPC either doesn't even call a third zepplin (which is a -must- for the achieve) or calls it at the literal last second before the match ends, making it impossible to have the time to target/kill it. I've also several times had issues where I definitely threw the bola (and I can see it flying up towards the zepplin) but it didn't count it for some reason.

Highest so far after about 2 hours is only 582, with a constant/average of about 460-480 when it does decide to work properly. Ready to just give up on it. Too broken.

Edit: Finally got it after 2 1/2 hours. Way too much RNG, latency and arbitrary times where the game just decides not to register a jump, hit or toss. I was so excited for a fun horseback riding mini-game; and instead I ended up with a really frustrating mountain of attempts all caused by sheer luck of the draw.

For those of you that use ElvUI for your action bars, I found that the supplied macro in the comments didn't actually work. However, the following macro does work:

/target Paper
/click ElvUI_Bar1Button3