Is it best to hold baby ig in the throws of adjusting in your hand or let it sit on your shoulder?

Answer 1

Baby iguanas will not stay on the shoulder. Because they are at the bottom of the food chain, and by nature, they will try to climb to the highest point possible. which will be your head, if you let it. But that's a bad habit to let it get into. They have sharp nails that will scratch you and you have no control over it. It can jump very fast and far and before you know it, it's gone.
Keep it in your hand, and let it "run" across your hand, then bring the other hand up, and let it run across that one.
You can train your ig to sit on your shoulder after it's been tamed and socialized, but for now, keep it in your hands. You will have more control, and the ig will actually feel more secure. Keep your hold gentle but firm. Remember to not grab it by the tail. Like all lizards, they can "drop" their tail to escape.

Answer 2

If you are inside, and you trust him, put it on your shoulder.