Hey Cliff! I don't know what ever happened to the old saying about the month of March coming in like a lion and goes out like a lamb... but it aint happening here! The winds have just now started to die down some here.
I've been using my drift sock quite a bit down here this past winter and spring, but am still pretty much a newb at it. Drift socks can do a real good job at slowing you down, but can be aggravating to use at times too. I had 2 and tried using both at the same time but that was too aggravating and not worth the trouble. If the wind is a constant blow out of one direction they're pretty easy to use. If the wind is variable, the drift sock can be a pivot to blow you around in circles. I use mine on a longer rope (20-30') and attach it to the transom because I fish directly under the boat. I think the soud of the water rushing thru the sock can spook the fish. If I was dragging a line behind the boat I would shorten the rope as much as possible and still keep the sock "full". One sock attached to one side of the transom will give you kind of a "diagnal" drift wich will put the wind blowing on the side of the boat that the sock is attached to and won't slow you down as much as you would think. I compensate for this by using the electric trolling motor to "straighten" the boat out so the wind is eith at my back (preferable) or in my face. With the wind blowing at your back, the wind will have less surface area on your boat to push you with and trolling motor power use will be minimal. With the wind in your face, trolling motor power will be greater... but you'll have better control over the boat and be able to make a straight line run better than without a sock. Especially in variable winds. The trolling will also help keep the sock "full" incase the wind dies for a few minutes.
I'd go with the 36" or bigger, but 36 oughtta do well on your boat.
Now one important aspect you may have overlooked is drift sock color! I bought a blue one because it was cheap and on sale, if I had to do it over again... I think I'd go with a Perch or Shad pattern!!! Hang a treble hook off the end of that bad boy and you could prolly get a couple Mucksies or a big Pike!!!
Maybe you should start a poll on the board as to which drift sock color people prefer?