Sch + Whm will be far superior to 2x Whm or 2x Sch, though I will say 2 Sch is the worst of the two. Over-all I have no issue Scholar healing. AoE healing is the roughest part, primarily after large damage bursts on the group but its still managable. I find the healing ST to be far better with shield providing that extra edge. 20% heal is AMAZING to combine with your big shield heal and can keep up a tank real well, particularly using the shield as a buffer before damage even starts.