I don't tension the head over the point where I want to use it, but I do stretch it by pressing onto it with the palm of my hand. I think the head collar on the inside of the bearing edge should not be bent.
When tightening, I try to get an even pitch alla round at low tension already. I listen for the moment when the lowest pitch gets established, and press the head for the first time, then true the head pitch all around at this point, then repeat the process until the pressing doesn't chajge the pitch anymore. Once its even, I just tighten the head in small, even increments. Doesn't have to be a star pattern, just the same increment on all t-rods. Press the head again, then correct any discrepancies.
When tightening, I try to get an even pitch alla round at low tension already. I listen for the moment when the lowest pitch gets established, and press the head for the first time, then true the head pitch all around at this point, then repeat the process until the pressing doesn't chajge the pitch anymore. Once its even, I just tighten the head in small, even increments. Doesn't have to be a star pattern, just the same increment on all t-rods. Press the head again, then correct any discrepancies.