Something I noticed about the starters’ Gigantamax forms is that they themselves don’t get any bigger, they are just equipped with items that make them giant.
Rillaboom has a giant drumset, Cinderace has a big ball of fire and Inteleon’s tail lifts it up 50 feet into the air.
Nothing important, just thought I’d bring it up since all other G-Max become kaiju size beasts.