I'd also amend the healer "Keep the tank at max" to "keep the tank alive". A good healer will judge where to keep the tank to avoid even coming close to death and do other things accordingly.
Max health is the best, even if not always necessary, but just "alive" isn't good.
When the tanks are low health, they might trigger their longest cooldown or check closely what's going on with the healer in case they are attacked by surprise or something, leading to unnecessary distraction or avoiding they pull yet another annoying mob.
In a PUG, you might be a good healer, the tank doesn't know it (yet.) They'll know it near the end, meanwhile show you can make the tank happy.