You will not see a large improvement with 1 week of regular review. At most, you'll see a few points of improvement, and anything else would be due to test material variance.
If you are done with content review, then starting FLs would be a prudent decision provided you take two days to review the exam thoroughly, and then a few more days (up to a week) to review any apparent weaknesses revealed by your FL via additional discrete and passage practice. Taking an FL would give you additional insight to create your own FLs by compiling practice passages and discretes and completing them under exam conditions (timing, exam length, etc).
If I were in your position, I would do the following if content review was completed.
12/15: Break day
12/16: FL 3
12/17-18: Review FL3
12/19-21: Practice passages/discretes
12/22: Break day
12/23: Mock FL made up of randomly selected practice passages
12/24-25: Christmas. Eat, drink, be merry.
12/26-28: Review FL
12/29: Break day
12/30: Mock FL
12/31-1/1: Review FL
1/2-1/4: Practice Passages
1/5 Break day
1/6: FL 2
1/7-1/8: Review FL 2
1/9-1/11: Practice Passages
1/12: Break day
1/13: Practice drive to exam area, drive home and start FL 1
1/14-1/15: Review FL 1
1/16-1/17: Practice Passages
1/18: Have some fun, scout testing area conditions as if taking exam that day
1/19: Practice drive to exam area as if taking exam that day, DO NOTHING MCAT RELATED
1/20: Exam day, don't drink coffee