Does anyone have one? Could someone help me out here?
I've got one and reallly like it.


Should one end of the shaft "float" or just touch the magnet?
Yes one end should be touching the magnet and the other just a small fraction of an inch off the second magnet. Slide the magnet to get proper clearance.

It says it will do a 24" prop so the prop turning full rotations are not required, right? I am running a 13X8 and it will not fully rotate of course.
12" props will spin completely. The prop does not need to rotate all the way around. I believe size is limited by the ability of the magnets to hold up the prop

If well balanced should the prop just sit horizontally?
Prop should sit horizontally when balanced.

The cones should be a snug fit on the shaft, Make sure your prop hole is clean and free of ridges, burrs or other defects. This would put the prop off center and lead to a false reading.

Compared to the finger tip balancer the top flite will be more accurate. The finger tip balancer will be "balanced" but the top flite will do just a little better job.