I need some suggestions for the last 12 cards or alterations.

4 ornithopter
4 myr retreiver
4 arcbound ravanger
4 frogmite
4 disiplce of the vault

4 welding jar
4 cranial plating
4 shrapnel blast

4 black artifact land
4 red artifact land
4 darksteel citadel
1 mox jet
1 mox ruby
1 lotus petal
1 mana vault

Obviously I'll be using some proxies, but I'm looking for 8 more non-creatrure spell/artifact and 4 lands, unless you think it could do with something else. I'm tempted to use 4 blue artifact lands, Thoughtcast, and a talismen of some sort, but I don't know. I don't know much past Champions so if there's anything better to replace something tell me.