Rookie balancer mistake

Okay so you're talking about the rear of the hub being longer, I misunderstood that. And FWIW that's not a great way to take an inside measurement, it's not going to be accurate... you really need an inside micrometer. Get a solid repeatable number on the crank snout and let your machinist get that I.D. measurement. (at that point I'd have him hone it too if need be..you're already there). I don't ever heat them, I like to be able to get them off without drama...
Fluidampr specifically says not to heat certain models, and for others they say not to heat above 250 or 280 so if you're dead set on heating it read your instructions...