Here is a link to the Seafarer Manual. Doesn;t say much about the InstaLift, but does mention to use a short shaft motor. I have a Seafarer 31 with the lazarette, but it has an inboard diesel. The lazarette has a piece of wood bolted to the front edge of the opening where the doors are, but it looks like it was just added in place of any lift mechanism.
http://home.comcast.net/~ker-plunk/seafarermanual.pdf