Hi, im french so i will try to speak english like i can xD.
Im 15/16hc actualy and for garajal we were DK tank (me) and pal/drood tank. The better way for tanking him before getting high ilvl is to keep your army for the end like a Defensive and offensiv CD, max your shield for the mele attack and spam your AMS !
AMS take the bolt than the Minions shot on you and its a heavy source of damages.
Blood shield protect you from mele attack.
Use your trinket (with dodge its better) and your DRW for the shadow attaque that u cant absorbe, and say to your healers to give you their CD every time they can after u use all yours.
After the enrage, use DRW + trinket and use AoD as a defensiv CD, then wait for your life goes down a lot and use Death pact.
Dont forget to keep an Icebound fortitude (WITHOUT GLYPH !!!) for this moment.
Pal can also BoP u whitout losing aggro
I hope it was helpfull to you and sorry for my (very) bad english XD.