I use plastic half clips on my grocery-getter since it helps me not have to worry about my feet slipping off the pedals. I'm not sure they would help much at a high cadence but you should try that for yourself to see.
I find the clips I use are somewhat shoe-specific and different shoes fit differently into them. Of course, some of my shoes are Hoka One-One's with over 1/2" of foam under the sole so that's an extreme case.