>Everyone I speak to seems to favour 3.5hp or below. Will the 4hp be too powerful?
I have a 4HP and I don’t find it too powerful (as long as the bracket, if used, is strong enough). The disadvantage is just the weight and size of the motor. Outboard size required all depends on the conditions and how fast you want to go. In flat water and light winds the boat is easily driven with little power, but as the wind and chop increase more power is needed. Those that only envisage using the motor in light winds will say that a small motor is fine, other will say choose one with more power. Also as the water gets rougher, the prop needs to be deeper.
The most wind I have motored in so far is force 4/5 in “estuary” conditions, not the sea, where the 4HP transom mounted motor needed full throttle and cavitation of the prop was starting to be a problem.