Home made E50 for racing?

The question is not about detonation with 50% ethanol. It's does a gas carb have the metering block's to supply the increased fuel volume to run 50/50? I run e85 to a motor at about 12.5:1 compression. My gas carb is insufficient. I'm betting you run lean no matter how much you turn the screws up? If someone has experience with pushing the carbs limits? I would be interested.