As you know cats don't really give you any feed back, so you really need to set sails by apparent wind, and understanding the boats polar is a must. They seem to like being over reefed, and loosely sheeted on the main. Even if it says 1st reef at 16-20, throw the first reef in at 15, you loose about 0.1knt, however the boat settles down, and feels much nicer.
As mentioned, going downwind, or following seas, you spend more time slowing them down, again over reef, and maybe bear off. Sea anchors, while some use...not recommended, in fact some brands specifiy not to use, will void insurance even.. can actually increase the chances of burying the bows...sea anchors can limit the bows from floating over swell.
Overall they are extremely safe boats, just feel very different from monos..recently was on a passage to NZ in a cat, had a bit of a blow, large confused seas...while 80% of the monos just hove-to, all the cats kept going..sure would have been best to turn and run with, however we just reefed down, close hauled, set the autopilot, went and made a coffee, sat in the saloon, spent the night watching for wind shifts/speeds, and course, and kept dry/warm.
Sure in super heavy weather, a mono would be a more comforting thought, knowing if you get knocked down, fair chance your going to roll up, however when cruising, you spend 98% of your time on anchor and the advantages of a cat are amazing.
You will learn heaps of little things that each cat likes with sail trim, and difference over a mono.
For example, having such a large beam, going downwind, instead of boom brakes etc, just a rode line off to a cleat and back to a winch..simple, easy and safe.
Again with a large beam, and long traveller, you can rig so you never touch the main sheet, just use the traveller..just simplifies things a little.
Flying a sym kite and gybing is the easiest thing in the world, and amazing feeling of cruising downwind, only a couple knts off true wind speed, super stable, none of that side to side rock, and worrying about accidental gybe of a mono.
Sail trim of course is a boat to boat difference, and your mono experience will come in handy, just try a small adjustment, feel the boat respond, with either speed increase or decrease, another handy one is to set autopilot, and watch the trim required to keep course, small adjust on sail, or balancing sails, suddenly zero trim input..they really do respond, just different ways of feeling it, it's not through heeling, or through the helm..
Overall, plenty of cats with wanna be sailors have sailed around the world, many times..normal rule that the crew will go to pieces before the boat does, just over reef, sail by apparent wind speed to boats specs, and possibly most important thing...keep your standing rigging up to scratch,
Yes, a bit of a rant..each to their own...just don't be put off by the old sea dogs that talk about safety of a cat, good chance they have never done any sea miles in one...