Thats almost how i did mine, i just did a rectangle because its easyer and you get no waste. I made 5 in less than 30 min. I didnt use a hanger or anything, i just clip it to tank. Depending on how many we need to make I could break out the sewing machine.
Ohh yeah, and i double layered mine, i dont know what micron it equals, but if i dont change it in about 7 days it starts to overflow out of the top of the sock. I think its a pretty good match. works great. super cheap!