Very nice! I have made a few lately with various kinds of yarn, and I've found the drape and weight of the yarn REALLY make a difference in the fit of the hat. Generally I find the the green loom is perfect for my head, and the red too small for my 10yo daughter, so I'd say the green is equivalent to an adult sm-med size head circumference. I believe in sized hats I wear a 7 1/8 just for a point of reference.
I just finished one out of two strands of a boucle last night on the green loom, just a simple roll-brim hat, and due to how stretchy the yarn is it's actually a bit big.
I think you did an awesome job of making the stripes come out nice, they don't always do that on the kk.