Okay, I've been working this one for quite a while now so I thought I'd post about it.
Even at lvl 85, this is a really bad trial for a MNK. Wamoura are strong and are more than happy to take you to the limit. Wamouracampa and Wamoura Princes use Heat Barrier (a blaze spikes effect for approx. 50 damage per strike) which may be the absolute worst thing for a MNK to face. Beyond that, you can pretty much only fight on firesday; there's nearly never any fire weather to give you a boost. Finally, to get to the best camps, you pretty much have to spend points to go through the staging area.
Now that we know the problems, let's talk location:
1. Best case scenario, you get a party to help you kill wamoura princes just past the gate. A full party can easily go through all the princes in the area by the time they start to repop. If you don't have a party, I wait just beyond the gate and see if anyone else shows up.
2. If yu don't have a party, go for wamouracampa in halvung. They're several levels below the princes. Head west to the zone that boarders H7 and H8. Past the first door is a lone freebie. Once he's dead, head to D-7 where you can find several in a tunnel (I start at the top and move down).
Strategy:
As a MNK, I feel that damage per hit is the most critical factor, closely followed by healing and then hindering enemy TP accumulation. Once Heat Barrier is used, you'll be wanting to hit much harder than the damage you're taking. Afterall, what good is it to be hitting a thousand times a minute if you're hitting for 30 and getting hit for 50? I'd rather hit for 100 or 150 slowly if I'm getting hit for 50. To get this damage, I use gear such as Melee Gloves, Amemet Mantle +1, and Thew Bomblet as well as meat for food. I also use Footwork as soon Heat Barrier is used, Poise shoes, and Melee Hose. I add the Melee Crown for strength plus subtle blow.
I sub DNC for most healing. Start with a chi blast (careful, they do link) with penence. As soon as it's in range, hit it with box step to lower its defense and save up a finishing move and then use Drain Samba. If you are planning on using 100 fists, now is the only time to use it (100 fists + heat barrier = epic fail). Keep using box step as you go until you get 5 finishing moves and then reverse flourish; for your 50 TP investment, you'll get 60 back. Now, as soon as the wamouracampa uses Heat Barrier, use footwork, with the right gear, you'll get a better damaged dealt to damaged sustained ratio.
Good luck and happy hunting!