One way of increasing the sail area for very light wind days is to add a jib.
I have done this very successfully on my Adventure (also my AI) and it works well but you need to be mindful that the tolerance (as you have identified) that the boat has towards carrying extra canvas is very small.
I have reported on my modifications in other posts on this site but basically the approach is:
1. Beg/Borrow/Steal/Buy/Make a suitable jib - mine is from a Topper (I believe) sailboat - about 1.8sqm - so it just about doubles the sail area of the std sail - more than enough for my sailing environment & risk profile
2. Stay the mast - the mast can't take the extra pressure of holding much more canvas aloft in a breeze and bends like a noodle so you need stays. I have a system of running backstays and a single (doubled) forestay that allows the std sail to be used on its own and the jib to be added as & when conditions permit. N.B. the jib is set 'flying' not 'hanked on' to a standing forestay. In fact staying the mast dramatically improves the sail shape of the standard sail in any sort of breeze (at the expense of being unable to roller-reef/furl in my implementation)
3. use a circular jib sheet so that you can't lose the sheet when sailing
4. probably add a padeye somewhere on the foredeck to attach the tack of the jib (you need to be careful not to upset the balance of the boat when you add more canvas and moving the centre of effort too far forward would be inadvisable so attaching the tack of the jib to a point behind the very bow of the boat is likely to be best - my setup works very well & the balance of the boat under jib is improved if anything over the standard Hobie mainsail-only set up where the centre of effort is set very conservatively and very far aft)
5. add some cleats to belay the jib sheet
You also need to be very methodical and disciplined when sailing with the jib and conservative in your decisions to deploy it - the amount of line in the cockpit increases significantly and it can catch on anything (especially the drive - I frequently pull mine when sailing with a jib), tacking and gybing require much more preparation and care, and of course you are at much more risk of an unexpected capsize due to gusts.
It all adds to the fun though and you do get much better light-wind sailing performance. Sailing such a tiny boat as this with 'full" sail, so to speak, is very entertaining and can be quite challenging - to set up as well as to sail.
Personally I love the excitement, risk and challenge of sailing the kayak as a kayak and nothing would persuade me to add any sort of ama to mine... not that I would wish to try to influence you in any way (lie, lie)