Delfino honestly works out more in Jigglypuff's favor than in R.O.B.'s, due to the fact that the numerous high platforms and stage formations provide her with a number of positions at angles which R.O.B.'s projectiles won't reach her, and he is forced to move into Jigglypuff's zone, and he can't use these positions for himself in any beneficial way. In addition to that, the formations which involve water provide Jigglypuff with the ability to use her Rest's invincibility frames to prevent a spike, b-air or f-air gimp on the side of the stage, on top of being able to cancel her rest after hitting R.O.B. with it either to kill or add on a number of percent damage that can put R.O.B. right into kill percentage via another rest. Due to the stage being immense both horizontally and vertically on the majority of its formations, she can live past 130% through DI and momentum breaking on all of R.O.B.'s smash attacks.
R.O.B. on the other hand, can use these same vast horizontal and vertical advantages to force Jigglypuff to chase him if he's leading, or he can stay out of her zone until the player develops a strong feel for his opponent, or he can just attempt to add up percent damage through R.O.B.'s projectile capabilities. Just as well as Jigglypuff can, he will be capable of surviving the majority of her kill moves until an estimated 160%(excluding Rest), on several of the stage formations.
As for rating, I would say this stage plays at a 7 for Jigglypuff against R.O.B., out of 10.
I left out some critical details for you to test on your own, since I clearly can't just give out all of this information after putting in so much effort to figure it out for tournament play, but Jigglypuff can also use the stage's walls at several formations to kill R.O.B. under 60%(on the start of the sequences). Guaranteed.