should i stack stam

ok so i have a 394 il 195 hp unbuffed my shields are at 200% 300 when my trinket proc should i now or at any point start going for stam gems rather than mastery gems

http://us.battle.net/wow/en/character/azgalor/Lanexx/simple
Only reason I've found a good use for more stam other than whats on gear is H Yor, but that's just switching to 2 stam trinkets instead of 1 stam, 1 mastery.
reg mode ds is a joke to tank but i noticed the times i was hit on heroic morchok had a few oh !@#$ moments is why i was asking
If you have no problems living until your next DS, you don't need more stamina. If you do, then you need more stamina.

The amount of stamina required varies severely from player-to-player.
oh ok well i have alot of oh !@#$ moments so i might just do that
Might want to have a look at your rotation and priority then if you have a lot of those.

Does your guild log your raids?