Looks like an interesting book. I second the recommendation for “Patriot Pirates.” That was a good read.
Chris Stoesen
https://payhip.com/ChrisStoesen
https://cstoesen.blogspot.com
I think for the lantern sail, look at extending the yard longer on top. Look up images of a show. That should be similar to what you are looking to do.
https://www.google.com/search?q=dhow&oq=dhow&aqs=chrome..69i57j0l3.2724j0j8&client=tablet-android-samsung&sourceid=chrome-mobile&ie=UTF-8#imgrc=0Bs_JCpWMXr1EM:
Chris Stoesen
https://payhip.com/ChrisStoesen
https://cstoesen.blogspot.com