I'd consume carbs before lifting. I read a study a while back that showed no increased protein synthesis with carbs + protein post workout compared to just protein. Plus you'd want the energy to lift intensely. Carbs are best eaten before a workout IMO. Even if carb sensitivity is better after a workout you will lose some of that stored glycogen before your next workout. But if you're trying to gain weight, just eat a shitload of carbs (within reason of course) all day long. No reason to pick specific times.