taco -
A lot depends on how well you want the arrows to fly (tune). You can certainly find a compromise between the two, and you might actually get away with it. Unless you're very lucky, the two arrows will require different parameters so yeah, you're going to have to retune.
The first line wasn't a wise-crack. I have some bows that I just enjoy shooting and can shoot several different types of arrows from without changing anything. At 20 - 30 yds the difference isn't severe and I don't worry about it. On my more "serious"

rigs, you can bet the tuning is a lot tighter.
Viper1 out.