On rigging a small homebuilt boat
While I am not really a fan of sprit rig, it does get a lot of area up high. The sprit does not need a lot of weight. It can be a nice 7/8 to 1" diameter piece of spruce, which will give a nice, springy spar. It also allows a short mast. Consider, though, that this is for small sails, under around 75 sf.
If you are considering lateen, consider an ACA canoe sail. They’re readily and inexpensively available, both new and used.
I have also happily used Balogh Sail Designs full batten sails. They reef well on the battens and can set up loose footed.