We can all help you with this, it sounds like fun.
The information we need is floatation of your AMA's, if not published, just throw one in the pool and try to sink it, we need the weight at which it submerges. This will determine the boat width and sail size.
I'm just guessing here but they look like around 180 lbs, if you make the boat ten ft wide you should be able to support a sail around 50 sq ft.
Your AMA's will need to be out of the water when not under load so the aka bars will need to be bent a little or raised above the deck ( and easily removable).
Your hull/ mast receiver cannot support a rigid un-stayed sail so get that out of your head. You will need a 7/8ths dia aluminum rod about ten inches long with a ball on the end ( I suggest something like a Scotty ball rod holder as your mast base just dropped into the mast receiver hole.
Wind surfing sails are the most advanced sails out there right now and there are many double wall soft wing sails avaliable that you may be able to retrofit (instead of design from scratch, which is very complex and I don't know of many sailmakers who have the knowledge required, as wing design works on totally different principles from conventional sails).
You will need to order the bigger sailing rudder from Hobie and put it on ( about 30 bucks).
When you make the aka bars plan to cover with trampoline material strong enough to hike out on because with that much sail you will not be sitting in the seat much.
Your sail is not going to stand straight up it will need to pitch back quite a bit at the top ( at least two feet) or else the boat will just dive.
Your mast topper will be a simple 4 point star of carbon or fiberglass rods about a foot long each leg (or long enough to clear the sail 360 degrees) with a ball in the middle. From the end of each rod you will run a spectra line (high test low stretch line) down to the bow padeye, then to pad eyes that you will need to add near your rear aka brace ( not in the center of your AMA because the have to counteract some of the huge forward load). Your rear padeye is mounted too forward to be of any use so you will need to wrap a line around the rudder gudgeon and put a clip on it to tie your rear stay line onto.
Your main mast will be wierd looking because it will need to be flexible fiberglass and bent ( like a windsurfing sail).
It will be a center external boom ( just like windsurfer sails, but will need to be adjustable in length (for trimming)). The rear edge of your sail will have a fiberglass or carbon rod the full length of the sail. The sail will be pulled taught between the front mast and the rear rod. You need to design so the sail can spin freely 360 degrees, so if you get in trouble you simply let go of the sail and it goes to a harmless neutral position ( no load or driving force like a weather vane). When in neutral the sail is a symmetric wing so it has no driving force or drag, this is kind of important and something windsurfer sails don't have or need.
For rudder control just buy the Hobie ball rudder handle, and get a piece of 3/8 PVC water pipe, drill a hole thru both sides on one end and loop some light rope like a lasso off the end of the stick and loop it over the ball, that's your tiller.
To put the sail down it will be attached at the back edge of the center boom by a wing nut (you will turn the wing nut in or out to adjust tension on the sail), when done for the day you unscrew the wing nut pull the boom off, then just roll the sail up around the main mast.
Your sail control line will be just a single line attached near the back of the boom, just tug on it to engage the sail and you will take off like a banchee, I see no reason you wouldn't be able to hit 20 mph plus with this boat (2x plus wind speed).
The mast is just held between the two balls, to remove you just unclip the stays, and the mast drops and can be easily rolled up and stowed (just like you stow your paddles on the bungies).
Here is a suggested profile that you can try (this would be the profile at the center boom, all the other ones would be proportionally less.
The widest point is a percentage of the length (about 12%), and the distance back from the front to the widest point is also a percentage (about 12%). Basically you take the length of the spar * 12% that's you width, and 12% back from the front is the widest point, pretty simple stuff. I just used soft foam blocks (1/2" x 1.5", like couch foam) slipped into cloth sacks that are glued or sewn (it's called darning (just ask your wife, it's a sewing term most women know what darning is) (not trying to be sexist here)) to the inside of the sail at each attachment point to maintain the spacing under each batton (pretty simple).
If you slit the front leading edge of the sail (between the battons), this will allow the wing to fill with air and make it a totally rigid wing (like a parafoil), and will keep the wing from fluttering like a flag at high speed.
I suggest instead of starting with the above advanced design, you start out with a extended pocket design (most windsurfing sails are of this type), basically the leading edge is a long double wall pocket (about 25% of length), then trailing into a single sheet for the remainder of the length, way cheaper and easier to make, and less complex, yet still pretty darned efficient. All the windsurfers I know have 5-6 different sails, and new designs come out every 6 months, If you talk to some windsurfers, they will likely sell you one of their older couple year old sails that is antique hopelessly outdated, and they will never touch again (these guys are all intense and really know their stuff, you can learn a lot from them). Retro fit that on your boat (it will save you a year of design)
If it were me I would not make it pointed at the top (like your pic), make it square topped similar to the Hobie kayak sail, the bottom doesn't need to be such an extreme angle though. The trailing edge will be bent (full width at the center boom), about 7/8 of the length about 1.5 to 2 ft below the center of the boom, and about 50% length near the top (it will look like a bow and arrow bow under tension). Your main mast will be slightly bent like a bow also.
When done you will have the most advanced wing design out there today in my opinion light years ahead of anything else out there.
This will be really expensive to make (about $300 bucks in materials), more than double what it cost me to make my wing, but it will be much more efficient.