The bow eye should , IMHO, be below the bow roller. When fully winched up
the eye should be using the tower roller as a stop so the eye should be
installed with that in mind. If there is an adjustment raise the roller so
your eye will be further above the waterline. The reason for this placement,
the boat needs a stop to keep it from creeping forward while towing.Also
winching the eye tight up against the roller keeps the boat and trailer
from bouncing around. A nylon strap instead of a cable is a good idea too.

--
Ron White
Boat building web address is
www.concentric.net/~knotreel