Here's the thing.. Your air:fuel mixture is influenced by a lot more things than just a number satmped on some main jet.
The mount of oil in the fuel affects how lean or rich the mix is. The weather and altitude affect it.
Jets themselves are supposed to be flow-rated so an accurate number can be stamped on them but who knows how careful the manufcturer was? Some of them just drill a certain hole in a jet and dont flow test it.. they just stamp a common number on it. The same size of a hole is no guarantee that two jets flow the same amount of fuel.
Another thing that affects lean/rich mix is how much air is getting in. An air filter (dirty or clean, big or small, etc) affects the ratio. The carb and intake manifold and intake port surfaces and sizes also have an effect on the mixture..
And there are lots of other things that affect the mix.. So, unless you have the exact same bike as someone else, you should be wary about blindly following someone else's recommendations. Start with the #62 but be careful and do plug chops and protect yourself anyway.