I was over there in late May last year. The trades were on and off, mainly off. Some years can be better than others during the transition from winter/spring to summer trade patterns I understand.
Industry Bay is a couple of mile stroll from the lee harbor of Port Elizabeth. There are a couple of nice wrecks around the harbor mouth worth diving on btw.
The launches can be tight, rock rimmed and if the trades trend north or south of east I would expect wind shadow and gusting winds with lulls. There can be some nice swells there with rock to go with however.
Regarding kiting off the lee side of high islands with offshore winds? The call on that is easy, don't do it. Way too much work, kites in the water, yarded kiters and getting blown off island. Reminds me of kiting during root canal surgery, all things in their place. Kite off the windward side, that is if suitable launches exist.
Bequia just made Photo of the Day, more images HERE