As an aside the 5(?) of us that were o nthe stirlign crusie proved that sdhort isnlt necessarily bad - as 3 of us (an SR4, Me at 5m & a 6.?m) popped out of the shelter given by the Kinkardine bridge and the firth widened (so the average wavelength of the mess changed there was only ever one of us having a comfortable(ish) ride.
One thing that can also work (but very wavelength / shape dependant - especially in a smaller rib) is to open up and literally skip from wave top to wave top. If you get it right it;s brilliant, but it is incredibly hard work & you cannot afford to loose concentration at all as you need to be feathering your throttle second by second to launch you to "fly" the trough or slow you so you land on a wave top rather than the face of the following one. (you need to keep your eye on the wave you are on, the following & certainly one if not two the other side of that one.
And if the wavelength s wrong, "tack" through them - by changing the angle you hit them at, you change the effective wavelength, BUT run the risk of being thrown sideways & / or getting soaked.
+1 for the passage planning. I have waypoints up both sides of the lochs where I used to go out in an 11' Dell Quay dory.....