I must say I’m a bit surprised to hear so many people had so much trouble with Oaks. Back when my wife (well, now she’s my wife, girlfriend back then) encouraged me to start playing the whistle, all I had was a really lousy Waltons that sounded horrible. She couldn’t stand it, so she got me an Oak after I had played for only a couple of weeks. I loved it, and still do. I guess I just didn’t know any better, so I just worked with what the whistle wanted in terms of breath.
I think it probably is a good idea to try some other whistles if the Oak is hard for you, but I would recommend going back to it regularly, because once it starts working for you, you’re likely to really like it.
Steven