The strait headjoint is a bit more uncomfortable than a curved one would be. I played one in college a few times that had a curved headjoint. However the reach is not unbearable for me. I'm not the tallest person, but I think I'm tall enough to use the strait head. I'm starting out with short sessions at a time to get my hands used to the playing position and maybe build up a little strength so I'll get used to it better. The last thing one would want to do is push too far and end up playing with bad hand position because their hands are already tired. That will only make things worse rather than better. Although... it's hard to put it down sometimes with such a cool sound!! I LOVE those overtones!!!!
I'll post a video if I get a chance before I get distracted by something else to talk about.
In the meantime here are some clips of alto flute music from Amazon: