Stability is important, whether on a bench or standing, I dont shoot from a bench much as I normally shoot heavier chamberings, standing is preferred.
On the bags a stable posture so there's the least movement/sway of the top portion of your body/torso.... keep breathing normally. If you slow down the breathing or hold it you'll feel the blood pressure rise, feel the heart beating and your muscles moving slightly (palpitate?) with the heart beat....
Same goes for standing with the breathing, I find anyway, when the rifle is brought up to aim... get the shot off ASAP once the target is acquired else the FATIGUE will start the movement/tremors (or is it just me??

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Stable stance, I dont lock my legs, particularly the rear shock-absorber leg slightly cranked ready to roll.......
If shootin the 44 lever, forget the above, just rest in on yo hip and get leverin' yiiiiiiiiiihaaaaaaaaa cowboy