I use the cascade Pima cotton also. They have a list of yarns that you are allowed to use. It should print out when you print out the patterns.
Oh yeah, when I first started making these my hands hurt so bad from crocheting them. I would do the wax thing to make them feel better or get my husband to rub them. I have knitted a couple of pairs but I prefer to crochet them.
Do you make them for a certain area? Have you gotten in touch with the main people out west that started this? They will send you all the info and info to send your clients along with the knockers, like how to clean them and they will even make you some business cards with your info on them. I have a lady, here that just calls me with orders that I just call her my supervisor. What state do you live in? Do you make them for a hospital/clinics or for the state? If you ever need any help or support please let me know. I have a couple of pairs on standby. Oh and for swimming you use a different kind of yarn. It has more acrylic in it. It is also on that list. If you can't find it let me know and I'll send it to you.
Have a great weekend !!!!!