Post limit.
Also, as good as Showdown Castle is, you might want to give thought on replacing it with Machina Armored Unit. My entire build is Earth and Machines, and it works wonders. Spending fuel on Fortress to beatstick/take out a monster with it, while summoning something with MAU is pretty frustrating to deal with. Particularly with how heavy Karakuri can be on the backrow. Of course, with Heavy and MST everywhere, Showdown Castle has it's place with it's "when destroyed" effect and obviously carries offensive momentum, rather than defensive. Your call.
Also, as good as Showdown Castle is, you might want to give thought on replacing it with Machina Armored Unit. My entire build is Earth and Machines, and it works wonders. Spending fuel on Fortress to beatstick/take out a monster with it, while summoning something with MAU is pretty frustrating to deal with. Particularly with how heavy Karakuri can be on the backrow. Of course, with Heavy and MST everywhere, Showdown Castle has it's place with it's "when destroyed" effect and obviously carries offensive momentum, rather than defensive. Your call.