While decreasing distance does translate into 'larger source' apparent size, the falloff of intensity of light increases greatly!
This is with a light only 3' from the subject...
...And this is with same light 10' from subject...
Notice how much darker the background is in shot 1, because the Inverse Square law of dropoff of light intensity makes the decrease in light so much more contrasty than the subject
For the OP, you need a larger source for the Main to keep the light soft, while moving the Main farther away to reduce the contrast of the shadow vs. highlight. You can also put a Fill light close to camera position on the side opposite where the Main is positioned.