What is a good moveset/nature/EV spread/item for Slowking?

Especially in the context of building a team around him, Tangrowth, and Mega Scizor

Right now I have a Slowpoke with a Modest Nature and the Regenerator ability. I was going to teach him Scald, Fire Blast, and Dragon Tail and give him an Assault Vest. I wasn't sure if my Psychic move should be Psychic, Psyshock, or Future Sight.

Any advice would be appreciated.

Also general build discussion thread.