Size isn't as important
I have an 1980 Hunter 27' with an 8hp Honda long shaft four stroke on a garelick mount. The wave height isn't so crucial, but the distance between waves is the problem. Had a bad scare last year trying to get back to my dock last year in 45 mph winds. I had to go straight into 3 foot waves with a high frequency for about 45 minutes, the nose would bury itself under a wave, the outboard would be screaming, i would lose steerage and get pushed sideways until the outboard got some "grip", then the process would start all over. Going with the wind was as comfortable as could be...My thanks to who ever invented beer. I sure had my share once the docklines were secured!!!!!