I've used a Nelson Rigg cover for all my bikes. Sold my ST1300 this Summer as well but kept my Falcon Defender cover. I have the Large and it's far too big for my FZ. That Dowcover you're looking at seems to be a similar product in construction. I love my cover.

Just last week I picked up the Nelson-Rigg UV-2000 half cover in Medium and its been working great keeping dew, rain, and sun in the summer off the bike. Fits the FZ perfectly.