The positive offset moves the wheel in wards to the center of the trailer There will be more clearance between the outside wheel well and less on the back side.
Since the mounting of the wheel is no longer on center when looking at the wheel with the hubcap on, the depth of the wheel will appear less deep. if one was to use a hubcap with a spinner on the end that would make the spinner stick out more from the tire. A half inch is not allot to worry about and when ordering the
axle you could make it longer to make up the difference if you wanted to. But you would always use an offset wheel. Make sure you buy an extra wheel for your spare tire.