I'm not a huge fan of heights so the first time I rode Millennium Force I just looked at the track directly in front of me going up the hill, kind of like I was watching a POV, to distract me from the height, which might help you. But after the first ride I realized it wasn't that bad and was really fun and exhilarating, and I started looking around at the view. And like other people have said, it's not that much taller than a 200 something foot coaster.
On TTD, I was really nervous in line and waiting to launch, but honestly, the drop felt like nothing. It was about half as intense as the launch and over very quickly. I think you won't have a problem with these coasters if you've liked hypers.