A place for a Magnezone on my Pokemon Diamond Competitive Team(Im kind of a newbie

[cybykillers]

so please help me)? Well my team so far is like this:

Scizor: sword dance, brick break, bullet punch(when i get platinum. but for now iron head), u-turn
Crobat: u-turn, bravebird, confuse ray, toxic
Dusknoir: will-o-wisp, gravity, earthquake, Shadow Sneak
Magmortar: flamethrower, focus blast, psychic, thunderbolt
Roserade: giga drain, sleep powder, attract, synthesis(can someone give me some ideas for a moveset for roserade? i dont think this one is good.
Empoleon: surf, ice beam, stealth rock, yawn/roar(which one is better)
Magnezone(want to replace someone on my team with magnezone):magnet rise, explosions, thunderbolt... ( please give movesets)

please give me pointers and give me some ideas on how to fix any mistakes you see.
I also want to add a magnezone into my team with magnet rise to cancel gravity when i need to but which pokemon should i remove? and can anyone suggest any movesets for any of these pokemon?

Thanks in advance!