Looks like mixed opinions, lol. A lot of people for and against, both online and in real life. I guess it does ultimately boil down to what works for me and my bp. Like I said, I'm not worried about anything else other than impaction, but I can always put paper towel or print paper on top of the substrate. I was also told since snakes are capable of digesting small bones there shouldn't be adverse effects even if he does swallow one or two pieces of substrate. I'm not ruling out the tub w/o trying it first, though.
Thanks to everyone for commenting so far.