If assembling a set of irons at D2 SW, what is a reasonable variance between clubs. I try to shoot for less than 1/2 SW, is this good or should I be looking for a tighter parameter?

Regarding Loft and Lie adjustments. After assembly I verify and bend as necessary loft and lie. My spec is 1/2 degree or less of spec. I then adjust lie as required by customer. Is 1/2* reasonable?