GT,
You don't have to make them all the "same".
Sear bars were fit individually to the luger, as were other numbered parts.
So- welding and fitting to a single luger is probably more effective than doing a bunch of them to some arbitrary "norm". Then they will likely require be fit to individual pistol/striker for use.
Line up a series of sear bars and observe the height, location, and shape of the sear nose- there is considerable variation on original bars.
Don't let the "perfect" preclude the useful in this case.