Two factors to consider: Time & Mess
My recommendation would be diamond blade and wet cut.
diamond blade really does make light work of slab (depending on thickness)
I cut 2" depth of 6ft x2 runs + 1ft width at each end.
Wet cut will keep the dust down but will create muddy puddles.
BE VERY CAREFUL OF USING HAMMER as this tends to obviously crack unwanted slab and may lead to more repair then intended
Dry cutting wears the blade quicker due to friction and creates heaps of dust
hope that helps