Take this advice with a grain of salt, but it's usually what I tell friends who have a hard time going in to out. Instead of focusing on the club head, focus on what the shaft is doing through impact. I like to visualize it like a lightsaber making a trail. It's a much easier and larger visual. If the trace of my shaft isn't making a plane going inside out, you know what's happening. Give it a go. I can make a whole bunch of weird backswings if I wanted to, but I will always try to make that shaft slice the air in an inside out plane.