Very quick--can be done in one evening. I would have liked a less wavy brim which is what the pattern picture depicted.
One alteration I made was to turn before the final round and then continue with the final row of sc (reason being, it naturally turned inward and down instead of curling up).
Insufficient explanation for the rosette. I threaded the tail down to the first row then while holding strip straight, weave the needle in and out every 1/4 inch or so; pull and gather to form a spiral as you please then tack the end in place at bottom to secure before you apply it to the hat.