Data comes from here: https://www.serebii.net/pokemonsleep/snorlaxratings.shtml Here shows the different comparisons of the different stage's sleep style frequency in each rank from Basic 1 to Ultra 5 then Master 1 to Master 20. I separated the two because the graphs will look skewed (master rank has alot of outliers). In the near future, I will make an indepth graph in:

1. the most to least sleep styles that are locked in a specific stage
2. shard reward in each rank in every stage

Some Findings:

1. Both Taupe Hollow and Snowdrop Tundra are the same in frequency in most ranks except Ultra 3 to 5. Taupe Hollow is much more balance in terms of frequency spread in Ultra rank compared to Snowdrop Tundra.
2. Again, both Taupe Hollow and Snowdrop Tundra have the most Sleep Style frequency in Basic 1 with 30.
3. Greengrass Isle Great 1 has the most Sleep Style frequency in all possible rank and stage in the game (for now probably).
4. Greengrass Isle is favored in getting the most Sleep Style across Basic to Ultra ranks and it is quite spread alot (though it doesn't show if there are duplicate Sleep Style from here to the different stages).
5. Great rank in Cyan Beach has the most frequent added Sleep Style with 57, while Basic has 44 and Ultra has 24.

Some Findings:

1. You're still rewarded some new Sleep Styles at Greengrass Isle even at over Master 10 compared the other three stage.
2. Just go to Master 12 if you really want new Sleep Styles of Blastoise, Vaporeon, Feraligatr, and Slowking, though they are available to befriend at early ranks. Beyond that, it's just a flex to rank up.
3. Taupe Hollow Master Rank 16 has one Sleep Style, which is Tyranitar (which you can befriend at Master 6 at earliest). Master 12 to 20 is just a dessert and that Tyranitar is an oasis, only reason to get that far is that Sleep Style. I'm not even sure if F2P can get that far.