I would recommend not doing a full body clip, he's going to need his hair for winter. Its VERY late in the year to clip, so I would reccomend a hunter, or trace clip if you must. But leave the rest, because it's going to get cold at night.
Plus if he's in his summer shed, he's getting ready to grow in his winter hair. (Wondering if it might interrupt the cycle?)
If you're in a Florida type enviornment ignore what I just said about the weather.
A few tips
-Clip with a 10 blade, dont do anything smaller or you could get a skin close shave!
-Clip against the hair in even strokes.
-Be sure to oil clippers before, inbetween, and after cleaning oil again.
-Be sure to stay safe!
Best of Luck!