If you are sailing in heavy winds keep your sails uncleated!, that way if your leeward bow begins to bury all you have to do is sheet out, and be sure to wear a life jacket, and sailing gloves. It is also a good idea to have a bob or some type of float on the top of your mast.
A couple of years ago we were in 18 MPH winds on my h16 with three of us aboard, we buried a hull but we just stopped and did not pitchpole, total weight of the crew was about 480 pounds, we were all the way aft except for my wife. Another time my wife and I were sailing in 20 mph winds, and while flying a hull I came up into the wind too much and wham, pitchpole!, ( my attention was on some girls on the shore and not on the helm), the jib back winded and I went flying and my wife fell into the jib. Neither the boat or us were damaged, but I had waxed the hulls so it took about 20 minutes, (seemed like an hour!), to get the boat back up because we kept sliding off! When we came in a guy at the dock told us he had some great pictures of our pitchpole, but I never had the chance to see them. Afterwards we celebrated our pitchpole with a beer at the Orleans Trail Restraunt at Stockton Lake in Missouri, it is a great sailing lake.
I have never sailed on a TheMightyHobie18 like you said you were going to look at , but I've sailed on a Hobie Miracle 20 and it was very stable, but all the lines and barber hauler running all over the tramp were a pain compared to the setup on an H16. I have also found that a furling jib, (at least on an H16), makes it easier to depower if the wind comes up suddenly.
It is also a good idea to practice righting the boat on a calm day. Once your hobie does decide you need to go for a swim you won't worry about it as much after that. A good book to read is Catamaran Sailing From Start To Finish by Phil Berman, it also has a lot of tips on buying a cat. I hope all of this helped and I did not ramble too much, good luck on finding a cat.

Banannahead.