I tried implementing this with view offsets (the same stuff tf2 uses internally to move the camera back when you play with model scale), and unfortunately it didn't work.
Instead, I increased the fov as a prop from 100 to 105. That
may help a little.
Additionally, I went into the thirdperson-as-prop code and fixed the lagginess of it. It's now much smoother, and doesn't interfere with the normal thirdperson (through the !3/!thirdperson commands, etc).