Are you going to be a "Trailer Sailer"?
I think that either model is designed to be similar in balance, since the fixed keel is heavier, but has slightly less draft. The swing keel is going to need more draft, but is slightly lighter in weight, so they seem to balance out. One positive of the swing keel is that you can raise it off the bottom if you run aground, while you need to employ other tactics with a fixed keel under the same circumstances. Best advice is, do not run aground. Someday I'll take my own advice. Your biggest concern should be how do you launch the fixed keel boat?; since it needs deeper water to get it floating off of the trailer. If you are going to travel to different locations as your post said, you may want to give preference to the swing keel.As far as heeling goes, there are several ways to address it. First, the boat needs to heel some when sailing, and in very light wind, you would even move weight to the lee side to give the boat some heel (it increases the waterline). If the wind is heavy and the boat heels too much for comfort, ease the sheets a little to spill some wind, or better yet, put a reef in the mainsail and use a smaller jib.The displacement weight of a swing keel is 4150lbs and a fin keel is 4550lbs. You need to add the weight of the trailer, outboard, and accessaries too. Look up your 1/2 ton pickup's towing rating for the answer.