Nice work. Looks real good. One suggestion would be use a D ring instead of the O ring. Will get you a few more weaves through it and make little stronger and little less Lilly to distort weave if pulled to hard.
Be careful with a plastic buckle sometimes they aren't very strong,my schnauzer pulled hard on it once and it came unsnapped.I use metal shackles for any medium
or bigger dog collars now and all is good.