I won't be much help, I had to abandon Ricky's methods when I found it too fiddle because I made mine half size but what I did was to check my labelled points went to the corresponding one on the other pieces then needle turned the corners, my fabric had started to shred with too many unpickings.
If you can stick to Ricky's methods and crack it I'm sure you'll have a great technique for the future.
It made me jump getting this notification, I had just started quilting it again last night after months of neglect