Really any absorbent material will work just fine. What I have noticed is U-haul pads allow you to go longer without changing the liner, and just changing pee pads, just like you are doing. U-haul pads really need to be inside of layers of fleece by no sew or sewing method as over time they tend to get thin after a year or so! I have a 4X2 with one little girl and a 5 X 2 with two sisters, so I switched to fleece sometime ago and learned to sew all my liners, lol. One last thing, just make sure you wash your fleece with vinegar, detergent., like free and clear, and I use dawn sometimes. I always test all new fleece to make sure the liquid immediately is absorbed and the area is dry soon after. Other than that, Have fun with fleece!