Hi Bob!
I personally don't agree with the other Mike's comments about water ballast. If you do enough reading on the Internet you will always find a few people who come up with some kind of dooming statement about water ballast, but the truth is weight is weight whether it is iron or water, a pound is a pound is a pound. As for where it sits in relation to the bottom of the boat of course the lower it is the better, but without going to a weighted bulb keel or shoal draft keel, the water ballast is the same as lead in any other boat. Volvo 60 class ocean racers use water ballast, they have a tank on each side of the boat where water is pumped in or out depending on the tack, that water ballast is not bellow the water surface when heeled over, but this is irrelevant to wetting surface(which really is only an issue of getting what, another 1/2 knot of speed out of your boat? most mac owners are cruisers at heart not racers anyways) Gravity pulls straight down the difference of half your ballast being 1 or 2 feet off center has little to do with a boat with such a small beam. The studies of macs all point to a tender boat in the first 5 degrees of heel which turns rock steady beyond that. Heeling factors involve much more than ballast, hull design is the biggest factor.Do a little more research and you will find many excellent articles that dispel each myth of water ballast. The nay sayers were rampant when this technology first came out, over the years there are fewer and fewer of them and most of the originals now have been won over and see the inherent benefits of this technology.Let's face it water ballast is the best thing that ever happened to the trailer sailer. With out this system in place thousands of trailer sailers would not be able to enjoy sailing. In addition just look at the sales numbers of Mac water ballasted boats in comparison to others to see that their must be something right about these boats.However Bob, my main concern with your post is that you plan on towing with a "regular car". While a 26 whether a classic or an x will fit the other two requirements of being easy to sail and load and un-load, towing with a regular car is not going to happen, at least not for very long or safely at all. Those mac's weigh around an average 2200 lbs. Once you start puting in all the stuf you want to have in the boat it is easy to bring that trailer weight up to 2500-3000 lbs. This weight is well beyond the recommended towing capacity of any car I can think of and well, well, well beyond the reality of safe towing. Remember that let's say you have a vehicle capable of towing 4000 lbs and you are going to tow a 2500 lb boat behind it. In ideal conditions such as flat, low altitude back country roads this will be fine until you add anything unexpected or higher highway speeds into the equation. Towing that boat on a highway at 65mph would be asking for trouble (Winds), any mountain driving would be out of the question (Not enough power) , and God forbid running into icy or raining conditions or a sudden traffic emergency would put you right on the edge of a disaster. (Jack knife) Even though you are under your ideal towing capacity, in an emergency or less then ideal situation you might find the boat towing the car instead of the other way around. We towed our mac 26d with a 1999 4 door blazer with a towing capacity of 5000 lbs, but you definetly always knew that boat was behind you. Now we have a 2002 trail blazer with 5800 lb towing capacity, it is much better, not because of the increase weight you can tow, but because the trail blazer is a much heavier and larger vehicle which makes towing much safer. (Bigger is always better when push comes to shove in towing) Another thought to take into consideration is the massive amounts of wear and tear on transmission and brakes you will put on a car maxxing out its towing capacity.If you are really going to tow with a car, I think you will need to reconsider your boat and possibly look at a smaller mac, like the 21 (1100 lbs) or the 17 (800lbs).Keep in mind that much of what I have written assumes you want versatility and safetly in towing your boat, things could vary a bit if your situation is different or if you are willing to take some risks, if you only have to go a mile or two down a back road to and from your house to the boat launch, then sure, maybe you could get away with it forever, but once again that would be under ideal conditions with no problems encountered. All it would take is one slippery boat ramp or your trailer wheels slipping off the edge of the ramp and you would be looking for a kind face to tow you out amongst the crowd of angry boaters waiting to use the ramp you have just tied up.I hope this helps you a bit, feel free to post any other questions you may have.