the fiberglass part has a bracket that just won't fit with the "over-the-top" style wipers. you have to cut out notches for them. it's a lot easier to do before you totally mount the top (ask me why, i know. ha ha.)
good luck with it man. where are you located? i know of a couple parts (sides, etc.) that i could probably pick up for you if the other top doesn't work out.