I posted this as a regular post in another thread, but I figured some people might want to know how it works, and how to get the best out of it. As we all know, currently, Dragon's Blood heals for 33% of your missing health, if you stack your class passives and buffs correctly though, you can buff it to 50% of your missing health. Anyways, as a Dragonknight, this is what you have to heal yourself, between passives, and buffs. This post has been re-edited to make a little bit more sense, and to clear up any misconceptions. In all accounts, we're agreeing that the Dragonknight in question has lost 10,000 Health, exactly. (PTS Numbers, scroll to bottom for one account of Patch 1.5 or Live numbers.)

• Dragon's Blood = Heals for 33% of missing Health.
  
• Igneous Shield = Major Mending: Increases healing done by 30%
• Coagulating Blood = Minor Vitality: Increases healing taken by 8%
• Burning Heart Passive = Increases healing received by 12%

With Green/Dragon's Blood
33% of 10,000 = 3,300
Final Heal = 3,300

With Green/Dragon's Blood+Igneous Shield
33% of 10,000 = 3,300
30% of 3,300 = 990
3,300 + 990 = 4,290
Final Heal = 4,290

With Green/Dragon's Blood+Igneous Shield+Burning Heart Passive
33% of 10,000 = 3,300
30% of 3,300 = 990
12% of 3,300 = 396
3,300 + 990 + 396 = 4,686
Final Heal = 4,686

With Coagulating Blood (Active)
33% of 10,000 = 3,300
8% of 3,300 = 264
3,300 + 264 = 3,564
Final Heal = 3,564

With Coagulating Blood (Active)+Igneous Shield
33% of 10,000 = 3,300
30% of 3,300 = 990
8% of 3,300 = 264
3,300 + 264 + 990 = 4,554
Final Heal = 4,554

With Coagulating Blood Active+Igneous Shield+Burning Heart Passive
33% of 10,000 = 3,300
30% of 3,300 = 990
12% of 3,300 = 396
8% of 3,300 = 264
3,300 + 990 + 396 + 264 = 4,950
Final Heal = 4,950
(This is the Min/Max, or the Maximum Buffs Possible. Note, only applies to the DK.)

What Does (Active) Mean?
It means in order for the healing bonus to be applied, the skill must be active. For example, in order for the Burning Heart and Coagulating Blood bonuses to apply, Coagulating Blood must be running it's duration, if it isn't counting down then you don't get the bonus heals. So. All in all, if you time it right, and have to recast Dragon's Blood while it's active, and you want the biggest heal possible, then you're going to want Coagulating Blood, because you can get up to a 50% missing health total heal, which is almost a 20% increase from 33%. I hope this post helped, keep in mind however, these numbers only apply to the Dragonknight in question, you can't stack the numbers on other people, the only buff that allows you to heal others is the Igneous Shield buff which increases healing done by 30%.

Other Random Numbers (PTS Numbers)
Let's say you make a Dragonknight tank with these buffs in mind, and he has 37,891 Maximum Health. So he's going to cast these buffs in order to get the most effective heal, now just for a general idea, 50% of 37,891 is 18,946, the decimals always get rounded in ESO, remember that.

Dragonknight Tank with 37,891 Health loses 24,807 Health. Leaving him with 13,084. About 34.5% of his total Health, almost in execute range but not quite.

With Maximum Buffs
33% of 24,807 = 8186.31
30% of 8186.31 = 2455.893
12% of 8186.31 = 982.3572
8% of 8186.31 = 654.9048
8186.31 + 2,455.893 + 982.3572 + 654.9048 = 12279.465
Final Heal = 12,279

As you can see, with the maximum applied buffs, the Dragonknight in question restored 12,279 of his Health, half of what he lost. As you can also see, the numbers get a little crazy on the PTS, and in general as you go up, because of all the percentages, I'll include one more number sample, from Patch 1.5, or the current patch as of this post. Lets say this Dragonknight has 3,974 Maximum Health, but doesn't use the maximum buffs that he can get and he's lost 2,974 of his Maximum Health with only 1,000 remaining.

With Green/Dragon's Blood+Igneous Shield+Burning Heart Passive
33% of 2,974 = 981.42
30% of 981.42 = 294.426
12% of 981.42 = 117.7704
981.42 + 294.426 + 117.7704 = 1393.6164
Final Heal = 1,394

Anyways, I hope this post is insightful, a Dragonknight can, in theory, stack enough buffs to heal himself for 49.5% of his Maximum Health, but he can only heal others for an additional 30%. Keep in mind that stacking all of these buffs means that you have to have them Active, Cast Igneous Shield, Cast Coagulating Blood. (By casting Coagulating Blood you active the Burning Heart Passive.) Then Cast Coagulating Blood again, for the full effectiveness to be applied, for example, you won't get the +12% of Burning Heart, or the +8% of Coagulating Blood unless Coagulating Blood is already active and running. (Also keep in mind the +8% of Coagulating Blood doesn't exist on the Live server, but the +12% from the Burning Heart Passive does.)