Any decent fabric shop should be able to make one out of sunbrella. Have a bungee cord sewn inside to help keep it snug so the wind doesn't blow it off. My boat was moored in the water all season and the cover worked and lasted 3-4 years. Should last longer if boat is on a lift.
There was a thread about this a while ago. Someone plastered silicone on the backside of their gloves and others have used a latex glove under the ski glove in attempts to keep hands dry = warmer.
That's a BIG lake. What part of lake are you going to? There's a handful of them, some are hard to find. Burnside, Beaver creek, Harmon Creek, Grider Hill to name a few.