I had a 16 foot boat with 50 HP engine. I installed a Cabelas plate and it slowed my boat too much. Fishing into the wind, I'd have to run more than half throttle to make any headway.
I sold the plate and found that tilting the engine up slowed the boat to around 1.2mph. It changed the thrust from straight back to up at an angle, causing less forward thrust. I fished it that way til I sold the boat. It worked great and didnt cost anything.