Without knowing hand size and grip type... Skip the Diamondback, it has a laser sensor. I have no experience with the FK so I can't comment on that beside it being a very popular ambidexterous shape. I can recommend both the Pro/203 and the Basilisk.

The Pro will be quite a bit different than what you're used to but it's one of the better small mice, IMO. It's only real drawbacks are the awful cable and mediocre scroll wheel. The buttons, shape, weight, materials, and sensor are all great.

I just bought a Basilisk a couple of days ago so I can't speak to it's lasting durability(a problem with Razer in the past) but it's become my daily driver. It took a shape that I already loved in the G502 and improved on it. It has some of my favorite buttons I've ever used on a mouse, including the best "sniper" button implementation so far, and my favorite scroll wheel. It's sensor, materials, and cable are all top notch. It's a bit heavy for some people still but, IMO, it's the best mouse Razer has ever made.