actualy every titan run I've done until now where I was paired with a SCH was much less stressfull on me than every single run made with a second WHM...

probably it is because u don't need a 1300 potency of healing (the only fight where I spam medica/medica II is demon wall when dps chose to ignore add... 1st stomp got nullified by SS+precasted Succor.... second and following Stomp are preshieldied and healed by a single medica I... Jump (the big aoe that crack the ring) pre-shielded by succor and reduced by the GT (I never rember that 10% dmg reductino GT) than healed by a medica II + succor (that will also work as preshielding for the next stomp)... and so on...

100% of the big aoe dmg that 2 whm will solve with double medica II can be solved with preshielding + medica II + succor (whose shiled will most likely work as a preshielding for the next aoe... unless u have dumb dps but that will still save the time and mana to heal them and u will use that mana and time to recast succor before the next aoe...)

it simply is a metter of timing the first succor before the aoe... once u do that right the aoe dmg for a whm+sch setupe is not a big problem... also note that adloquim is really better than cure II... with than in mind when couple with a whm sch focus on tank and whm focus on party helping each other when needed or when the section u'r taking care of is not in need of healing...

this is the point of view of a WHM that usually run 8 man content paired with a sch (guild mate that I usally run with) and can really feel the difference when paired with a second whm rather than a SCH...

PS: note that I still have to run coil... but as far as I've heard the problem there is the massive dmg on tank rather than the party... but still without personal experience I will refrain from comment on that untill I've done it myself with both healing setup