Sound ports are a fairly new phenomenon in the Ukulele world, but I have put them in all of my tenors and baritones for the last few years. They send sound back to the player, a valuable thing if you are playing in a large group. I am convinced they do no harm to the tone or quality of sound of an instrument. Here is how I do it.
Very slowly and carefully grind the edges and fit the wooden ring.
Until the ring fits tightly
A little sanding and the job is done. When finished and touched up, this will be an excellent installation. With this job done, It is time to box these ukuleles up.
And here they are, backs glued on and clamped down tight. In the morning the edge trimming and binding can begin.