I keep them an inch or so off the floor in plastic trays. The only reason is, my tent is in the basement and I don’t want my pots sitting directly on the the concrete floor. The concrete is cold and I’ve read that it may cause the root zone to stay cold, slowing growth. If you’re watering until the first sign of runoff, you shouldn’t have too much water sitting in the trays. You can always draw out the runoff if you get too much.
Don’t tell Kind soil but any time I get enough runoff to measure, I check it out of curiosity. It’s always been around 6 to 6.5. A little piece of mind goes a long way.
My usual watering in a 5 gallon pot when my plants are established is 1 to 1 1/25 gallons of Ph’d water every 4 days or so. My limited experience has shown that cannabis plants deal with underwatering much better than overwatering. The fabric pots help with overwatering but this method has worked for me.