Triumph & Disaster

I bought two shirts with puffed sleeves last year from the internet. Of course I bought it for the sleeves initially, but I just can't help but disliking the cut of the sleeves opening, where the sleeve is actually designed to be a half-sleeve with a wide opening, so it's a pretty big space for an arm!

So few days ago, I had some ideas to alter the sleeves as I'd still want to wear the shirts. So after tearing apart the sleeves, and re-sewing again, I got the below to show off.

How long would it take to finish up the remaining 3 sleeves?