For SCH I am full Crit. Crit shields on t5 make mine and the other healers job so much easier. DET on SCH is what I stack second if I can to help my fairy.

For my WHM I am currently mostly crit but working on a full DET build (just used my SCH stuffs at first).

Spell Speed is worthless. Every fight has set patterns. If people are not stupid or having crazy lag issues you never have to worry about casting faster.