Eh, let me think:
First off, I am NOT a competitive player. I know all about EVs, IVs, and all that stuff, and reading Smogon analyses for several years has given me an idea of various strategies for individual pokemon or entire teams. I ev train and all of that stuff, but only to play against friends, smash the CPU, or, very rarely, over wi-fi. Also, I will use "outclassed" pokemon over their "superiors" if I like said pokemon better. Overall, I would much rather have fun than win, although I do like winning, so you might not like any strategy I have for the above reasons, as I have little to no expierence in competitive battling. Most of what I have to say is somewhat common sence, but I'll give it a try.
Bronzong: Obviously defensive, but can somewhat hit back. Most sets involve gyro ball, stealth rock, and similiar moves. There are dozens of sets this thing can run, and it happens to be one of my favorites. If you are looking for an oddball, here is one I used to use on Battle Revolution, to make use of a shiny bronzong I got off the gts:
nature: quiet/sassy/relaxed. EVs: various, although maxing HP is likely a good start. Moves: Trick room, calm mind, psychic, flash cannon. Item: leftovers Ability: Heatproof
I used this in double battles alongside a spiritomb, which would use nasty plot when bronzong used trick room. Most players never saw it coming, expecting the duo to use a "common" moveset. Bronzong then calm minds a few times and starts hitting back. Suprisingly, I rarely got taunted. Also, everyone assumes a bronzong uses levitate, and most players won't risk using EQ to find out for sure. Going against the norm is often a good bet, at least for me.
Gengar: Special sweeper. Give it a choice item or a life orb and let it go. Hidden power is optional, and other moves, such as substitute, for when you think you can force a switch. You can try trolling with a focus sash and destiny bond, but weather and rocks will damper this.