I have the pauldrons of unnatural death, but I prefer the block and dodge on t7.5 with that, should I put 27 expertise in the shoulders, 41 stamina in legs, and put 27 hit/27 expertise somewhere else, and putting expertise/stam gems in the monarch crab.
I put +24 stams in blue slots, +16 defenses in yellow slots, and +41 stams in red slots to grab the bonus. If you'd rather switch up the yellow and red and put +16 expertise in red and +41 stams in yellow, that's fine, but regardless, you should almost certainly save your three unique gems for +41 stams.
I wouldn't gem the monarch crab with anything but stam or stam/def (since the socket bonus is good). Personally, I only drag it out on maxenna and patchwerk. Other than that, I use threat/dps trinkets. If I was going to use a stam trinket, then I'd use monarch crab over essence of gossamer if I had to choose one or the other. Being able to activate the dodge on demand every minute is far superior to an extra 3 stam and a RNG 4k shield proc.
You are getting to the point on your gear upgrades where you can start backing of gemming for stam and start gem more with expertise - even to the point of using 16 exp in red slots over 8 exp/12 stam. This will allow you to reach and surpass the expertise soft-cap.
If you want even more flexibility in terms of gemming, then drop mining and take up blacksmithing. The extra slots means that you can have one set of gloves and bracers gemmed for threat and another for stam/avoidance/etc. Mining limits you to just stam.
All you JCs don't ignore the Ruby Hare! 63 base stam, 2 red sockets, and 9 stam bonus. 72 stam + 32 expertise or 96 stam + 16 expertise are two good ways to gem it up. The run speed usage can be useful for tanking . . . I use it to run from the swarm on Anub'rekhan