The windows are for docking and manoeuvring mainly and the wheel is only supposed to produce 0.5g.
Sir, it's not the
force of gravity that is the deciding factor in the diameter of the grav deck.
Your true limiting factor is the speed at which the deck must spin, and the amount of 'gravity distortion' that will result from the relationship between the speed of the spin and the diameter of the 'wheel.'
If the 'wheel' is too small, it must rotate very, very rapidly. The resultant forces acting on the object would therefore be very different between the observer's head and feet-1G at your feet might be 0.75G at you head, or even less! If you think that occasional shifts in gravitational force on a boat or in a plane can be slightly disorienting, try having
every single movement you make produce such an effect! Constructing a very large wheel will not only reduce the amount of 'gravity distortion,' it will allow you to put more of your ship in the grav deck and thus reduce the amount of time spent in low-G. Additionally, the effect of the spinning gravity deck will produce rotation in the balance-regulating structures of the ear... 2 RPM or less is ideal, 7 RPM is tolerable in adaptable individuals.
Look it up on Wiki, man... good article there which will explain this to you, and which actually has the formula to find out how fast a given diameter grav deck will have to spin to produce a given gravitational force!