With that size doors, I'd definitely choose the wider casings.

All our interior doors are only 32" wide and we are useing 6'8" doors with transoms downstairs (10ft ceilings) and 7'0 doors upstairs (9 ft ceilings). Frankly even with our doors I really wanted to use 4 1/2 inch trim. We wound up going with 3 1/2 inch instead but only b/c DH wanted stained woodwork and the cost of the 4 1/2 inch width in stain quality stretched the budget just a little too far. (We're trimming all the windows as well as the doors.) I think it'll be okay on our doors and windows but still wish we could have afforded the 4 1/2" trim. I think it would have looked so much nicer.

With your wider taller doors and higher ceilings, I really think 3 1/2" trim will look skimpy. JMHO.