The right prop will not give you speed but tork. Most kicker props will max out at 3/4 throttle (in speed), an aggressive pitch will just slip unless there is lots of blade, so having said that evaluate what you have and what your looking at. You want a big blade, lots of surface aria, then pitch is last in importance.
Some of the props out there have small blade surfaces so you need to really look at it and take some measurements. Its as much an art as it is science because there are so many variables with each boat and set up.
What your describing sounds right to me, I wouldn't waist money on it, as it works and works good. Its very hard to fish in 6' seas so moving the boat like yours dose is very good.
PK