There's been alot of discussion about book numbers, I'd say checkout Zebekiya's post as I very much agree with his estimates he posted a few days back.
Technically, 672k or 674k is the start of the "final range" for SM (from Oldghost) so anywhere between there and 737k could yield the final prize. Zebekiya thinks 722k+, particularly the 733-735k is the sweet spot. On 2MJ, the 260k-277k (end of print) with 268k probably being the predicted range. I personally would buy any 2MJ 255k+, and any SM 720k+.
@ Jackpotchasing - With only two $1M prizes remaining, I don't think FL Cash is worth playing. The $20 Flamingo game, in my opinion, is a better buy since it is 92% sold through, has a $5M, two $1M, a $100k prize remaining, and plenty $20k, $10k, and $5k prizes out there. You can request the winning book numbers on Florida Cash for the $1M prizes to see where they were all claimed, and determine if there's a gap anywhere. It is possible 1, or both of those final prizes are from earlier ranges (and likely to not be claimed).