If you give a Zac a large Straxus he's going to ask for a new Scrounge with a special arm like no other. And if you make him a new Scrounge, a rolling disk of tragedy, he's going to want a Helex/Polyhex Titan that turns into the Smelting Pool to melt that Scrounge away. And if you make Zac a Smelting Pool Titan he is never going to shut up until you make a Spanner / Space Bridge Titan as its Autobot counterpart...
-ZacWilliam, yeah... that may be my favorite Marvel TF story...
I don't know about a Helex/Polyhex Titan, but you just gave me an idea. I'm planning on getting both Hasbro and Takara versions of Fort Max. Since some parts need to be swapped to get an actual G1 accurate Fort Max. The extra, now, may end up getting repainted into Straxus's Fortress, Darkmount.