I think using the grid was a good solution. It involved measuring distances. That's the idea. Using the mirror on the vase one is not really a useful solution. I wish you had just used grid on it too. Remember, this is prepping you to take on a realistic portrait in oil. You will need this skill if it's going to work for you. So stick with the grid. The next thing is learning to separate the shadows from the lights.

overall placement is there. Maybe go back on the squares with the features and double check some of the smaller shapes that make up those areas. Do a lot of rapid eye movement back and forth between the drawing and your reference. You might see some spots to make more accurate.