I think pally makes a terrible tank for hmgt to be honest, the mobs there do an insane amount of damage and you dont want to be multi tanking when you can avoid it.
There are a couple of ways to be succesful in hmgt, and all of them rely on your party members not sucking. First and easiest, if you have any combination of warlock/hunter/mage/spriest/rogue as dps, and they are GOOD at the CC side of their classes, you should have no issue. Warlock/Hunter/Mage means that at most you are dealing with 2 mobs, and at best 1 while the warlock's enslaved pet literally solos another.
The second is to have very, VERY good dps who can get the clothies down before they decimate the tank. Druids dont have any trouble tanking the mage guards or blood knights, but the warlocks and magisters decimate us.
From a tank point of view, you really want to gear up for stam over agi in this place if you have any options. As said above the melee dps in there are not the issue for druid tank - the casters are. Unless you have ideal dps you are going to be copping heavy burst damage regardless of your armor and dodge, and you need the hp to give your healer a chance to catch up.
You can probably heal hmgt with 1600 +heal and 600mp5 out of combat but if your tank isn't geared some of it will really challenge you - most notably the second boss.. you cant bug the debuff off any more so there is a tonne of burst damage to overcome, especially if the party doesnt let you recover before he starts going into arcane explosion mode.. it will decimate the party before the hots have a chance to work.. Id say stick to tanking and gear up for hp (staying crit free), and find a healer who is adequetly geared to support you.
Good luck on the trinkets, I have run hmgt at least 30 times and havent seen the tank trinket drop once -_- I have every other one of the trinkets as a feral druid, and not the commendation :(