There are no deadlines in my workshop so you can take your time and work at your own pace. Some students even had emergencies in the family or lost their jobs or had unexpected vacations, and they simply come back to the workshop weeks or months or even years later and pick up right where they left off, and I don’t treat them any differently and still answer their questions and give them in-depth critiques. That is one aspect of my workshop that’s unlike any other workshop out there–you get basically life-time mentoring from me. Ask any of my alumni students and they’ll tell you it’s true. I’ve been mentoring all of them for years now, and many of my very earliest students from 2010 are still constantly getting guidance from me in our private Alumni Lounge forum.
As for your question about drawing accurate, I have a specific set of strategies to cater to different situations and levels, including horizontal flips, modular grid system, visual assessment methods by matching distances, angles, negative space, and simplification. What you described (putting your drawing as another layer on top of the original) is one method, but that can’t be the only method you use, because when they two images are overlaid together, you’re not engaging your brain’s visual assessment that’s required for a reference to copy scenario–you’re just assessing one image that’s a composite of two different images. That’s useful for when you can no longer spot any differences between your copy and the original reference, but yours still looks wrong. If you’re not at that point yet then it won’t help you nearly as much as the combination of the other techniques I mentioned. You need to use all of them together in order to be able to draw accurately.