Hi, you indicate in your "against AD" build section that one should buy Cinderhulk + Sunfire, which is not a good option since both don't stack ! Also, i would suggest to start hunter's machete instead of talisman, since Zac does not rely on mana :)
Moreover, items such as Warmog's are op on Zac.
For Masteries, i'd recommend going 6/6/18 with 5 points in Fury (Sorcery is nice too) and 1 in Feast, then 5 points in Wanderer and 1 in Runic Affinity, then classic 18 on the green mastery tree.
Last but not least, i'd recommend 9 marks of attack speed for easier clears, 9 flat armor seals (not health, armor is much better for jungle clears and early resistance !!!)and 6 flat cdr blue + 3 scaling mr. And the most important : 3 Movement Speed Quints, which are just op and super useful on any tanky champions.
Ty for your guide !

Please notify me if u wanna see others parts from Zac in this build ;)