I have had four 2x4 and two 1x2 GuineaDad liners for over two years and in general am happy with them. Even though I follow directions and wash mine in cold water and hang dry, mine have shrunk over time to where there is an approximately 1-1 1/2 inches gap at the end of the 2x4 ones and I use the 1x2 liners to fill in the gap. I believe one can gently stretch the liner while it is still wet but I have not tried that. The end of the liner also happens to be a high traffic area, where I normally will put in an extra pee pad to be switched out every 2 days. Since I have a large number of small liners to fill in the gap, it isn't an issue for me. One of my friends just sewed ten 8" x 16" liners for me when we got together to bake cookies last month. I won't have to buy anymore from Etsy; my friend was surprised at the cost of liners on Etsy.
Regarding the respiratory problems, my piggies do not stay in the pocket long and they like to run in and out of it . Just to be safe, I removed the pocket from two of the liners and use them as additional fill the gap liners (using microfiber towels underneath) at the end. For the other two liners with pockets, I kept them on but flipped them underneath so that they will still be available in the event I want to let the piggies use them.
I've noticed another Etsy seller now includes a pocket in her cage liner design. My biggest issue with the GuineaDad liners is that the grey color is dull.