I only have 2 snakes and might add a third, so it didn't make sense for me to build a rack that could accommodate multiple tub sizes. I built the rack for 41 qt tubs and use those for my snakes, even though they're only 150 grams or so. I also simply added several hides to help them feel more secure in a larger space. Right now they have 5 per tub (hot, cold, mid, humid, half log). I'll remove hides as I replace them with larger ones.