Neat approach.
Since the 900KB model ships with the compressed file, is there a file size below which the model overhead just eats the gains?
Curious where the crossover is.
I tested with 100 MB files because anything larger takes a long time to evaluate. The actual target was at least 1 GB, and in that case I would use a 100 MB model (Shannon entropy rules).
I also tried it on a 100 MB Photoshop file and was able to compress it down to 45 MB, whereas ZIP could only get it down to 60 MB. So yeah still not losing gains.