I have only ever had one bloat type episode and it was a stress bloat..not from food.
My dogs have always eaten from the floor (I have had newfies since the eighty's)........never raised
I do feed two smallish meals..no dry food...at least one bone a day...and fruit and veggies. When we go water training I feed a very small meal and I keep my dogs calm before and after meals, though I will go for a walk after a meal in the morning....but I think the size and type of food is very important.
I never restrict water and i do not give my dogs very cold water on a hot day, but i will let them have some icecubes (small number). Not sure if all of this is relevant, but i have been rather lucky so far. I have dealt with a few emergency bloat episodes of a friends dog (wolfhound) and it is very frightening....katy had an episode after her major operation, but I used the pressure points on her and tubed her on the way to the vet....she never had any further treatment and just stayed at the vets when we went to work for a fortnight as just in case, 8am untill 5pm......And she had a Gastropexy a few weeks later for safety.