How much flour? Is the quantity of water correct, it seems such a lot? Do you think if I halve the recipe the challahs would come out okay? Judging by the quantity of water there's no way I'd fit so much in my bread maker.
Sorry for leaving the flour out... I fixed it. It's a regular 5-lb recipe so yes, you need a big mixer. I use a Magic Mill/Assistent (or whatever it's called at its present incarnation) and just love it. It's large enough and powerful enough to make a huge dough easily; highly recommended.
I've used part white and part pastry ww flour (as much as I would like to do more, hubby prefers white!) and it still came out excellent so you can definitely do that.