I keep my hair permed and have for years and found the results seemed to vary more with the technician than the actual perm itself. I don't know about your area, but where I live, it's becoming much more difficult to find expert perm specialists. I think the lack of popularity of them right now makes it harder to find people with lots of experience, which is how you get a perm that you love. Young, talented stylists don't seem to even want to give them at all. That said, I have very fine hair and have best luck with exothermic perms. I'm a retired stylist and finally just started doing my own. One downside of perming white hair is that it tends to cause yellowing.

I would also recommend an exothermic perm, I even use them on bleached hair. The secret to a successful perm is the winding. I see so many stylists doing it the wrong way, they comb and grab the section in to a point and then wrap in paper to roll up. It's called fish tailing and a bad technique as you get an uneven perm. Then the timing is essential, even though the perm may say one thing, it may be another. White hair is harder to perm so maybe they've not left it on enough time. A good stylist will check the perm every five minutes to get the correct timing. When you call a salon, inquire who among them is the best at perming white hair, then give them a try.

My sister had a perm about a year ago. It was a technique that was suppose to give her "beach waves." It was totally fried. Just awful. I'm guessing, since it was suppose to be a new technique, the stylist probably didn't have a lot of experience even though it was in a very reputable (expensive) salon. Also, her hair is very fine so that probably added to the difficulty.