No, not heavier at all. With a floating bridge you don't need to worry about the twisting torque that is so present with a glued on bridge. You have the downforce and that's all. With an electric, you will be using lighter strings, and that will lessen the downforce, and your neck angle will also have a lot to do with it. If I were you I wouldn't have a huge breakover angle on the bridge. I'd probably start with a 1/2" high bridge and get my neck angle to work with that height. The higher you make the bridge, the more neck angle will be needed and the more downforce will be there, too. Most electric guitars have a string height above the body at the bridge that is about 1/2" high so I'd start there. A very standard light X brace will do fine, and use a small spruce bridge plate too. No need to use a hardwood one.
Mark Swanson, guitarist, MIMForum Staff