Marvin the difference between 6/0 and 8/0 is thickness the 6/0 is thicker than 8/0, i use 8/0 for buzzers. i usually just get my thread from my local tackle shop but i have been getting a few bad rolls lately so will be on the look for a new supplier, there should be plenty of people on here with advice of where to buy it. also i use black alot for buzzers but you can use almost any colour of thread to make them, if you check here you should find a few types. hope that helps.
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