Need help building the coil for a crystal radio set?

Im building a crystal radio set and I'm a little confused because 100 different websites recommended you use different gauge magnet wire and diameter of the pvc tube.. i have a spool of 22, 26, and 28 magnet wire and i have some leftover 1.5" and 2" pvc in the basement. Will these "laying around the house" items work ok.. and if so how many times should it be wound?