rear wheel sensor with Specialized Allez frame

Hello,

I'm a first time poster and a new cyclist. I just got a Cateye Strada Cadence computer with a rear left chain stay speed sensor and crank-mount cadence sensor. My Specialized Allex Elite frame has rear chainstays that hug the wheel and then flare out. As I'm new to this, I don't know the name for this setup but it doesn't have the traditionaal consistent taper from bottom bracket to rear hub.

The problem is that b/c of the closeness of the chain stay to the spokes, there isn't room for the speed sensor to be mounted to the inside of the chain stay. Am I overlooking something? Can the sensor be mounted "on top" of the chain stay or does the sensor line need to be vertical for it to pick up the magnet?

Thanks for your help!

Ktaadn