I have an 18' fiberglass bass boat (champion) with a 1982 150hp v-6 Blackmax mercury outboard. What is the best prop pitch for this setup - I'm not looking for top speed, but rather better low speed control and faster planing. The current prop is SS and I'd like to go to aluminum. How can you easily tell what pitch the existing prop is? Currently the boat will top out at 58mph, which is way faster than I need (40-45 would be adequate).