I'm trying to decide whether 
is better, or whether 
is better, or whether I should just skip the enchantment all together. Sunfire cape just works extremely well on him, but if I get Cinderhulk than I can't really get sunfire without wasting stats. On the other hand, I do believe that generally speaking cinderhulk is the better enchantment on him since he wants to be a really beefy tank who just sits around dealing percentage health damage.
Any thoughts?
Well i had an 88% winrate on him for a long time in season 5.. I typically just went full tank and CC'd the hell out of the ADC over and over again.
I'd prob build him something like this:
I also played him much differently than you i assume.. well, at least in terms of goals. I figure the longer im alive the more Q's and E's i can use, and chances are if im sticking to the ADC, my thornmail will kill him faster than any ap i try to build. Being the initiator i like to dictate the flow of the team fight by lasting as long a possible.
been playing him recently and i have to say i love rylai on him; gives you perma slow to help peel and slow down the enemy team.
I usually go bc i like to have burst for early ganks, but some games cinderhulk i think is better...really think you just have to look at what you're dealing with and/or what your team needs
into tank is pretty nice too...possibly picking up sorc boots and a late linadry
I'm trying 
and don't see passive useful on him. I mean If I get Q champ is already stunned making that passive useless. If Q don't connect then passive is still useless.
AP Amumu can't a tanky initiator ( Q or R are too good) and if I do Q or R then i won't have enough sustenance to get out alive. Tanky Amumu doesn't have much damage to kill champs in mid/late game.
I'll pick it based on team comp.
