Float switch question.

[zum14]

So I'm going to order an apex lite and set it up with some float switches for auto top off and tank level and such. What I'm wondering is how sensitive the float switches are? By sensitive I mean how much does the water level need to drop before it makes or breaks contact. With my new sump the water dropped about 3/4" since last night in the pump area which makes the herbie overflow not run right. Makes since as the head pressure is changing. So if the float switches work within let's say 1/8"-1/4" of water level I probably wont have to constantly adjust one way or the other. If they require more movement then that I'll have to look into tunze with the optical eye. Thanks!