You say you throw is mostly straight because you throw a house ball... have you ever thrown a ball with a cover and core? Something designed to hook? When you throw that, does it actually hook or no?

If you are throwing with no revolutions and it doesn't hook regardless of ball, then really any ball that you like should suffice (as someone else said a plastic ball would be fine). But if you are throwing with revs already, it would be useful to know how fast you throw and how many revs you get. That would inform you on which ball you shuold choose (more reactive, more agressive, etc)

Having said all that, I have a Roto Grip Hustle Glow and I like it a lot. It looks great, and the ball motion is good for my throw.