NEVER play with your pH.
leave that to experts ONLY (I consider myself an expert and I'm scared of the off the shelf stuff)
if your really worried about pH (most fish don't care) then add some limestone to raise pH or driftwood to drop pH. that way it happens slowly and a little more naturally.
the pH readings you read are for wild caught fish, most fish you buy are commercially bred, they are even breeding discus in Asia in pH as high as 7.8 supposedly
stress coat should only be used when adding new water to the tank, and only enough to treat the water your adding, not the whole tank. it is mainly to remove the chlorine. if your fish are healthy they should not need fake slime.