101e it looks like the mainsail of the Puffer has a boltrope sewn into the luff (front) of the sail. Be sure to feed this into the slot on the mast as you hoist the main, keeping the bow pointed into the wind will as you hoist will make this much easier. This will help greatly in properly shaping the sail and it will actually make the boat a bit more stable. It's hard to tell from your pic, do you have all three battens in the sail?
Also try to keep the daggerboard all the way down in the slot when sailing upwind, more stability and handling.
It may seem awkward to tack if you are sitting more forward, but you'll catch on pretty quick how to move around things in the cockpit. This will help you balance the boat fore/aft when singlehanding. By keeping the bow down on the water the boat will handle better and be a little faster. Adjust your seating when your gf or others join you aboard.
It sure looks like you are having lots of fun, both sailing and searching for the best boat for you. Sail on!