Questions in Hollow Knight

I am trying 112% the game first try and i am stuck on the watcher knights, any charms or techniques for fighting them

(BTW already got the chandelier)

which is harder to beat?

Where do you think the knight stores geo

Is grubsong any good? bc I feel like it is

how did the maggot get that large shell?

what bosses are easier when in these 2 different states

IM ENDING THE "IS HORNET VOID" CONTROVERSY BY REMINDING THE FACT HORNET MAKES SOUL WHEN HIT, SHADES DO NOT!

Edit: im saying shades are made from void and do not give soul when hit but hornet gives soul when hit meaning she isnt void

which boss did you was easier when you found out their attack styles and how to dodge them