Yeah, it doesn't make sense, hence me posting here with my hat in hand.....
Yeah, I'm going to double-check the measurement. But to back up what I measured, I did run the bike and there was certainly excess noise due to the large gap on the exhaust valve.
So, what can it be?
Measurement error? Most likely, I am human. But I find it hard to squeeze in too-tight feeler gauges.
Took too much material off of the stem of the valve? Not likely, since I didn't touch that end.
Added too much hard facing on the valve? Doubtful, I can't weld like that and didn't try anyway....
Some dust/debris between the valve face and seat? I don't think so, especially since I ran the motor already.
Not enough oil between the bucket/shim/valve? Strange, since the other valves didn't change nearly as much.