Honestly, I would recommend redoing Lesson 1 and 2, but just 50 additional boxes for the box challenge rather than the whole set - that's usually what we recommend for those starting over if they decide to use official critique. While it's certainly not as easy a pill to swallow as starting off where you left off, it'll ensure that any holes of understanding or recollection about the instructions/earlier exercises are closed off, providing you with a solid basis rather than going ahead with potential pieces missing.