I have a question about stopping a cat.... So what is the best way to do this?
What are you trying to achieve? Are you looking to stop the boat as you approach the start line during a race? Or are you looking to stop the boat to take a break during casual sailing, etc?
For casual sailing, put the boat hove-to by backwinding the jib (sheeting through the windward blocks), pushing the helm to leeward, and completely releaseing the mainsheet. This will cause the boat to slowly drift forward on it's own and you can take a break from sailing (about as close to parked as you can make a Hobie).
If you're starting a race, you definitely don't want to go hove-to as you won't be able to accelerate for the start and you won't have any steerage. Pre-start handling takes a lot of practice and focus. You basically dump both sails, but if the boat starts to round up into irons, you need your crew to quickly sheet in the jib while you turn the rudder to pull the bow down, then as the boat begins to accelerate, you blow the jib and straighten the rudder. It takes a lot of focus, coordination, and practice to maintain position on a crowded start line.