I have been trying to lay out a 4 x 6 workspace and I can't even get a desk and chair in that amount of room let alone have space for me. I guess if you had a 4 foot wide space by 6 feet deep you could have a 4 foot wide desk by 2 feet deep and a 4 x 4 space for you and the chair. If you had a computer on the desk I don't know where you would write at though.
And keep in mind that Downs isn't even allowing that much space if his description is real and not exaggerated.