I know how the timing works and that I can file the keys myself, but what I asked is what keys people have used an had success with since they are sold in a wide range of advance.Once you remove your flywheel and tap the timing key out of the crankshaft, you can measure the thickness of the key. You should get a similar measurement to what we're getting here. Our key is .160" thick. Our goal is to advance our timing 8 degrees. We know every .006" we file off the key...affordablegokarts.com
File it yourself.