/cgl/ - Cosplay & EGL

I'm thinking of getting around to cosplaying at a con for the first time, and I'm planning on going as Finn from Adventure Time in about a month from now. I've still got the blue shirt and shorts from when I last attempted the cosplay thing when I was in my early teens, but I'm not sure on how to get the hat sorted. I wanna go for one of those hats that cover everything above the shoulders, rather than the ones that cut off around the neck as I always thought those looked kinda cheap, but since the former's harder to find, I might as well DIY one myself.

I could maybe try to get some cloth, take a few measurements of a hood on one of my hoodies, cut out some fabric for the hat's front and back based on the measurements, and stitch them together using a sewing machine or something. Hopefully that way I can get something that fits and comes out like the cosplays in picrel (w/ some space for a bit of hair), though I'm not used to sewing, so linking the front and back ends of the hat might be kinda tough. Are there any better methods or do I have the right idea?

I also want to try and make a "metal" arm like the one on the bottom-left of the pic. Currently, I'm thinking of getting an arm-length lycra glove and painting the arm's seams on to it, and I might try to get a bit more /fit/ before the con to better reflect the design. If there's another method any of you guys prefer then lmk.