I say make it a beater fixie. Make no effort to make it look nice or bad. Out on a real fixed hub for your safety and security. I have a spare flip flop hub I can sell you for what I paid for it. I've laced it up but never ridden it. Keep the front wheel or put on a matching one. Remove the rear brake.

You already have enough geared bikes. You can take your fixie out when you want that kind of ride. Now it suits a new purpose and you can justify owning it.

i say make a 66 inch gear for the winter. It's good for you.