We have a top zip sail cover on our 26. The zipper is at the front and the entire cover is left in place. It has caused no problems. It just settles in the jack lines our of the way and below the foot of the sail. I do like the pics I have seen on this post. The blocks on the choker are covered with leather socks and do not rub on the mast or interfere with the cover.
Rob Powers Respite 26C #50 Sidney BC