Solid hub prop..
 

How much of the prop shaft should be visible when a solid hub prop is put on? I know you have to put on the brass retainer to hold the locking tab and nut on, but how much of the actual shaft should show before putting them on? Changing out props and it's been a while since I had solid hubs and need to know what spacer to run on the back side of the prop...

The labyrinth seal must be inside the gear case.
What prop are you installing? Is it a floTorq hub or a cast in spline. Most of these set ups use this thrust washer.

Thrust Washer from BBlades Professional Propellers

Brett