Unfortunately the answer to most of your question is "it depends". I would use the Lost Tunic 100% of the time, but the others can swap around. Wrists are great in M+, and situationally good in NH. Jewel is VERY good for spike damage (eg Spell Blade, Gul'dan). Helm can be good if you need another cooldown (eg, if you're having trouble with bonds on Gul'dan).
For trinket, the Royal Dagger Haft is actually quite bad for Brewmasters. It calculates based on the full initial hit, which is often mostly absorbed by stagger. Infernal Contract can be good for high damage, like Spellblade or Gul'dan. More about trinkets here.
Stats look ok overall, but I would recommend enchanting for vers, not haste. 10-15% haste is more than enough - especially with the chest & 4p Tier 19. I have several sets of gear - one with high mastery for M+ or heavy physical fights, one with high vers/crit for magic fights (Krosus, Star), and a balanced set for general use.
If you are using combat logging, you can upload a log to the site checkmywow.com which will help breakdown your actions to see where you can improve.
A great source of information is the Monk Discord server: https://discord.gg/8rrYQtE. Check the pins at the top and the #resources tab for links.
From the resources I have at my disposal, and being able to ask top level Brewmasters this similar question, they've given me the following information:
For progression raiding, use the legendary chest (Sal'salabim's Tunic) and the ring (Jewel of the Lost Abbey).
For M+'s, the chest and wrists are good.
As far as trinkets go, like the poster above me noted, it depends. For high magic damage encounters (Krosus, Star Augur) I use the trinket from Skorpyron. That's because my specific raid comp lacks external defensive cooldowns, so I need the damage reduction for our progress.