My opinion, get all the ponies it will hold. An underpowered boat won’t plane with extra weight in it, and I won’t even talk about when it’s time to go......NOW!!! The motor also isn’t working as hard and works better and will last longer. Good luck with the choice. Merc and Yamaha are my choices, look at what the guides run, that speaks.
I came back and added this. Think of this; for some reason you have to go now and you need to plane ASAP. The smaller motor takes significantly longer to break over and get on plane than a larger motor. Depth and obstructions can change things fast also.