How Do You Measure Second Stage of 2-Stage Trigger

[Conaso]

As the title says, how do you measure the second stage of a 2-Stage trigger? If I get a 2lb reading with the first stage and a 3lb reading when the weapon fires, is that a 1lb second stage?

 

[Jefe's Dope]

Measure the first stage, finish the pull/second stage. Subtract the first stage from the total.

I'm not 100% that's the correct way to do it, but IIRC, that's what I did.