what's your opinion about nashor's tooth gragas or a bruiser gragas jungle with icebourne and red smite?

Im wondering about the itemization. I have been one tricking AP shyvana for months and her itemization is incredibly straight forward and simple. So that makes me wonder what warrants building fully against AD, AP, Tanks or whatever instead of just building the example build for late game? Also why whould you ever not build sorc boots? You need all the burst you can get right? And sorc would improve that. Are you going for a hybrid semi tanky semi burst thing? Cause even then theres a ton of AP and no other defensive items. Im just unsure how i decide what to build and when, while playing Gragas. (does going inspiration in your runes instead of going domination for sudden impact slow down your early ganks?)