You may also want to check out www.classicarchery.com
I use their fibers in my scope and have been very impressed with them, Bright Little Buggers and they come in long pieces.
I know they come in sizes .019 and .030, I use the .019.
I also flare out the end of the fiber slightly, this causes the fiber to increase in size slightly and seems to really brighten it up even more.
You can flare out the fiber head by after installing fiber in pin take a thin flat piece of metal and heat it and then touch it to the end of the fiber mushrooming it slightly.
They run about $10.00 to $9.00 for 3 sets they come in Red, Green and yellow, I know they also make a clear fiber for use with the colored light for your sight.