If your project has to fit properly, then you really need to make a swatch and follow through on what you learn from your swatch.
Now back to shawls. I finished two more of the wheelchair shawls. I didn't measure them but having used the same hook and worsted yarn, I figure they're at least approximately the same as the other two (the blue and the grey). Here are some photos.
The yarn used was Red Heart Super Saver Frosty Green and Frosty Green Fleck. I enjoyed working with the fleck particularly as it was something a little different.
All have been sent off to find new homes.